Big Bang: A Teoria(2007)

1 - The Conjugal Conjecture

After Sheldons mother and Leonards father share an evening together, everyone deals with an awkward morning the next day. Also, Pennys family arrives for the wedding ceremony, including her anxiety-ridden mother, Susan, and her drug dealing brother, Randall.

1 - The Hofstadter Insufficiency

With Leonard away, Sheldon and Penny spend quality time together sharing intimate secrets. Also, Wolowitz helps Raj get over his ex-girlfriend.

1 - The Date Night Variable

With his friends on dates, Raj must face his loneliness. Also, Wolowitz is caught in an argument between Bernadette and his mom, even while hes in space.

1 - The Skank Reflex Analysis

Penny is worried with how damaged her friendship with the guys will be in the aftermath of her sleeping with Raj while Sheldon becomes the leader of the paintball team.

1 - The Robotic Manipulation

Penny tags along on Sheldons first ever date; Wolowitz finds a new use for a robotic arm.

1 - The Electric Can Opener Fluctuation

When Sheldon learns the guys tampered with his expedition data he got from the arctic, he leaves to Texas in disgrace. This results in the guys following him, which threatens Leonards hope for some romantic time with Penny and the guys friendship with Sheldon.

1 - The Bad Fish Paradigm

Pennys first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.

1 - Pilot

Brilliant physicist roommates Leonard and Sheldon meet their new neighbor Penny, who begins showing them that as much as they know about science, they know little about actual living.

1 - The Proposal Proposal

In the eleventh season opener, Amy gives Sheldon an answer to his proposal while Howard and Bernadette struggle with some unexpected news.

1 - The Conjugal Configuration

Sheldon and Amys honeymoon runs aground in New York. Penny and Leonard discover they are uncomfortably similar to Amys parents. Raj insults physicist Neil deGrasse Tyson and starts a Twitter war.

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2 - The Retraction Reaction

Leonard angers the university – and the entire physics community – after he gives an embarrassing interview. Also, Amy and Bernadette bond over having to hide their success from Sheldon and Howard.

2 - The Military Miniaturization

Colonel Williams, an Air Force representative from the Department of Material Command sits down to talk with Wolowitz.

2 - The Deception Verification

Leonard and Sheldons friendship is tested; Howards latest foray into helping his mother has some disastrous side effects.

2 - The Decoupling Fluctuation

When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.

2 - The Infestation Hypothesis

A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

2 - The Cruciferous Vegetable Amplification

Realizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.

2 - The Jiminy Conjecture

Leonard and Penny struggle to recover from an awkward first hookup while Sheldon and Howard stake their best comic books on a bet to determine the species of a cricket.

2 - The Codpiece Topology

A jealous Leonard reacts to Pennys new guy by rebounding with Leslie.

2 - The Big Bran Hypothesis

Leonard volunteers to sign for a package in an attempt to make a good impression on Penny, but when he enlists Sheldon for help, his attempt at chivalry goes terribly awry.

2 - The Wedding Gift Wormhole

Sheldon and Amy drive themselves crazy trying to figure out what perfect gift Leonard and Penny gave them for their wedding. Raj decides he wants to settle down and asks his father to arrange a marriage for him.

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3 - The Procreation Calculation

The Wolowitzes life gets complicated when Stuart starts bringing his new girlfriend home. Penny and Leonard talk about starting a family. Raj explores an arranged marriage.

3 - The Relaxation Integration

Sheldon and Amy struggle with picking a wedding date, which stresses out Sheldon and causes him talking in his sleep. Meanwhile, Raj and Stuart fight over the attention of one of Bernadettes co-workers.

3 - The Dependence Transcendence

Tensions rise when the boys struggle to complete their government project on time and Sheldon tries an energy drink to stay awake. Also, Penny and Amy go to a “party” at Bert the geologists house, and Koothrappali learns Bernadettes true feelings about her pregnancy when they clean out the future baby room.

3 - The Scavenger Vortex

When the entire gang competes in a scavenger hunt designed by Raj, it brings out the best - and worst - in everyone.

3 - The Higgs Boson Observation

Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz.

3 - The Pulled Groin Extrapolation

Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.

3 - The Zazzy Substitution

The guys are concerned as Sheldon searches for an alternative to human companionship.

3 - The Gothowitz Deviation

Howard and Raj visit a Goth nightclub to pick up women while Sheldon attempts to build a better Penny using chocolate-based behavior modification.

3 - The Barbarian Sublimation

Sheldon creates a monster when he introduces Penny to online gaming.

3 - The Fuzzy Boots Corollary

Leonard asks a woman out after he finds out that Penny is seeing someone.

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4 - The Explosion Implosion

As Howard worries about fatherhood, he and Sheldon bond when they jointly assemble a model rocket. Meanwhile, Penny bonds with Leonards mother, Beverly, much to his concern.

4 - The Cohabitation Experimentation

When Amys apartment floods, she proposes a “cohabitation experiment” with Sheldon. Also, Howard and Bernadette are upset when Koothrappali learns the gender of the baby before they do.

4 - The Raiders Minimization

Sheldon gets mad at Amy for ruining one of his favorite movies, Raj and Stuart try to make their online dating profiles more appealing, and Leonard tries to play the sympathy card with Penny.

4 - The Re-Entry Minimization

When Wolowitz returns from space, he doesnt get the heros welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.

4 - The Wiggly Finger Catalyst

Penny plays Matchmaker for Raj, which results in him finding a girl he is comfortable talking to.

4 - The Hot Troll Deviation

An embarrassing secret of Wolowitzs comes to light, while Sheldon and Raj have a small war at work.

4 - The Pirate Solution

Raj must find a new job or be sent back to India, but Sheldon has a solution, which leaves Leonard and Penny dealing with Howard as a third wheel.

4 - The Griffin Equivalency

Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.

4 - The Luminous Fish Effect

Sheldons getting fired forces him to explore what life has to offer outside physics, leaving Leonard to take drastic action to snap his friend out of his funk.

4 - The Tam Turbulence

When Sheldon wont tell anyone why hes never mentioned his childhood best friend, Leonard takes matters into his own hands. Bernadette and Penny take out Rajs fiancée for dinner to get the skinny on her.

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5 - The Collaboration Contamination

Sheldon and Koothrappali confide in Bernadette when they cant handle Amy and Wolowitz working together. Also, Penny and Leonard learn new tactics for how to deal Sheldon from an unlikely source.

5 - The Hot Tub Contamination

Leonard and Penny must separate a quarreling Sheldon and Amy when their cohabitation does not go as planned, and Sheldon threatens to break off their relationship when Amy refuses to adhere to the bathroom schedule. Also, Howard and Bernadette find unexpected guests at their house when they decide to stay home from a planned vacation.

5 - The Perspiration Implementation

The guys take a fencing lesson from Barry Kripke and Sheldon finds himself in an awkward position when Kripke expresses interest in Amy. Also, when Stuart struggles to get female customers at the Comic Book Store, Penny, Amy and Bernadette come by to help him out.

5 - The Workplace Proximity

Amy starts working at Caltech which causes friction with Sheldon. Howard agrees with Sheldon who mentions this to Bernadette causing a big fight for the Wolowitzes.

5 - The Holographic Excitation

The gang celebrates Halloween at Stuarts comic book store. Meanwhile, Leonard seduces Penny with science.

5 - The Russian Rocket Reaction

Sheldon and Leonard get invited to a party at Wil Wheatons house, and Howard gets an out-of-this-world opportunity.

5 - The Desperation Emanation

Leonard realizes hes the only one without a girlfriend, while Sheldon wants to get rid of his.

5 - The Creepy Candy Coating Corollary

After overhearing that Wil Wheaton is entering a trading-card competition, Sheldon decides to enter it himself. Meanwhile, Penny sets up one of her friends on a date with Wolowitz.

5 - The Euclid Alternative

Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.

5 - The Hamburger Postulate

Fearing hes wasting his time on Penny, Leonard ends up making a connection with Leslie.

5 - The Planetarium Collision

When Amy doesnt have time to work on super-asymmetry, Sheldon goes to great lengths to ensure shes available to work with him even it if means accidentally sabotaging her career in the process. Raj doesnt want Howard to join him in hosting a show at the planetarium.

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6 - The Proton Regeneration

Sheldon goes head-to-head with Wil Wheaton for the role of the new Professor Proton. Also, Penny steps in to take care of Halley when Bernadette and Wolowitz both wind up on bed rest.

6 - The Fetal Kick Catalyst

Penny is surprised to learn she has fans of her performance in Serial Ape-ist when she attends Van Nuys Comic Con with Leonard. Also, Amy hosts a Sheldon-style brunch at Pennys apartment, and Wolowitz makes an impulsive purchase when he starts stressing out about the baby on the way.

6 - The Helium Insufficiency

In the midst of a nation-wide helium shortage, Sheldon and Leonard take desperate measures to get the supplies they need. Also, Penny and Bernadette download a dating app on Amys phone to try and find her a new man.

6 - The Romance Resonance

Sheldons latest scientific breakthrough leaves him feeling like a fraud; a romantic gesture between Howard and Bernadette causes Penny to up her game with Leonard.

6 - The Extract Obliteration

Sheldons relationship with Stephen Hawking is threatened over a game of “Words with Friends,” and Penny secretly enrolls in a class at the local college.

6 - The Rhinitis Revelation

Sheldons mother, Mary Cooper, comes to visit, but Sheldon is annoyed that she also spends time with the rest of the gang, instead of catering to his every demand.

6 - The Irish Pub Formulation

Leonard keeps an affair a secret from Sheldon, Howard and Raj.

6 - The Cornhusker Vortex

Sheldon becomes Leonards teacher in order to understand football, while an incident with flying a kite threatens Howard and Rajs friendship.

6 - The Cooper-Nowitzki Theorem

Sheldon and the gang are confused when a young grad student is attracted to him.

6 - The Middle-Earth Paradigm

Penny hosts a Halloween party, putting Leonard, Sheldon, Wolowitz, and Koothrappali through a new test of their social skills.

6 - The Imitation Perturbation

When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Pennys Halloween party. Leonard is shocked that Penny doesnt remember their first kiss.

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7 - The Geology Methodology

Sheldon and Bert collaborate on a research project, despite Sheldons embarrassment. Also, Penny and Bernadette coach Koothrappali on how to navigate his relationship with Ruchi.

7 - The Veracity Elasticity

In order to continue living with Sheldon, Amy lies to him about repairs being made to her apartment and they host an on location episode of Fun With Flags in Pennys apartment. Also, Leonard lets Penny decorate Sheldons old room after he learns that she has been secretly moving Leonards collectibles into storage.

7 - The Spock Resonance

Wil Wheaton interviews Sheldon for a Star Trek documentary where he reveals the ring and his plan to propose to Amy. Bernadette wants to start renovating the house and the topic of starting a family together with Howard is brought up.

7 - The Proton Displacement

Sheldon seeks payback when Arthur Professor Proton Jeffries asks Leonard for help on a project instead of him. Raj gets upset at Howard for crashing his night with the girls.

7 - The Habitation Configuration

Wolowitz struggles with moving out of his mothers house. Meanwhile, Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.

7 - The Good Guy Fluctuation

A cute comic book artist puts Leonard and Priyas relationship to the test, while Sheldon tries to scare the guys for Halloween.

7 - The Apology Insufficiency

Sheldons answers during an FBI interview put Wolowitzs security clearance in jeopardy.

7 - The Guitarist Amplification

A squabble between Leonard and Penny sees Sheldon playing mediator, though out of his own incovenience from the sitiation rather than altruism.

7 - The Panty Piñata Polarization

When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.

7 - The Dumpling Paradox

With Wolowitz AWOL with one of her friends, Pennys recruited to fill in for him on the guys Halo team

7 - The Grant Allocation Derivation

Leonard is caught between a rock and a hard place when hes responsible for distributing extra grant money. Bernadette turns the backyard playhouse into a hideaway from Howard and the kids.

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8 - The Tesla Recoil

Leonard and Wolowitz are furious after they learn Sheldon went to work with the military behind their backs. Also, while Bernadette is on bed rest, she asks Raj to do some digging when she suspects Ruchi is trying to steal her job.

8 - The Brain Bowl Incubation

After a successful experiment combining their genes, Sheldon will stop at nothing to convince Amy they should procreate. Also, Koothrappali is embarrassed to tell the gang what the new woman hes dating does for a living.

8 - The Mystery Date Observation

Sheldon, Wolowitz and Koothrappali post an online advertisement to find Sheldon a new girlfriend. Also, when Amy is coy with details about a guy she is dating, Penny and Bernadette decide to spy on her.

8 - The Itchy Brain Simulation

When a mistake comes to light, Sheldon makes Leonard walk a mile in his shoes; Penny decides to confront Rajs ex-girlfriend, Lucy.

8 - The 43 Peculiarity

Raj and Howard try to to figure out why Sheldon disappears at 2:45 every afternoon; jealousy arises in Penny and Leonards relationship.

8 - The Isolation Permutation

Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.

8 - The 21-Second Excitation

While the guys camp in line for a long-awaited movie screening, Penny and Bernadette invite Amy to her first slumber party.

8 - The Adhesive Duck Deficiency

With Leonard, Howard and Raj away camping in the desert, an injured Penny has only Sheldon to rely on.

8 - The Lizard-Spock Expansion

Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.

8 - The Grasshopper Experiment

Rajs parents set him up on a blind date, but just when he discovers he can talk to her, she shows interest in Sheldon.

8 - The Consummation Deviation

Sheldon tries to bond with Amys father, but when Howard lures Mr. Fowler away with magic tricks, Sheldon has no choice but to bond with Mrs. Fowler. Raj and Anu try to get physical for the first time.

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9 - The Bitcoin Entanglement

Sheldon tries to teach the guys a lesson after they cut him out of a potentially valuable Bitcoin investment. Also, a seven-year-old video reveals a secret about Leonard and Pennys relationship.

9 - The Geology Elevation

When Bert, a Caltech geologist, wins the MacArthur Genius fellowship, Sheldon is overcome with jealousy. Also, Wolowitz finds an old remote control Stephen Hawking action figure he invented.

9 - The Platonic Permutation

Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily, and Penny discovers that Leonard knows more about her than she thought.

9 - The Thanksgiving Decoupling

Sheldon protests when the gang drags him to Mrs. Wolowitzs house for Thanksgiving. Meanwhile, Penny and Leonard must deal with a mistake from her past.

9 - The Parking Spot Escalation

When the University reassigns Sheldons parking spot to Wolowitz, their fight affects the whole gang.

9 - The Ornithophobia Diffusion

Leonard and Penny try hanging out as friends on a non-date, but end up purposely ruining each others chances with perspective dates. Meanwhile, Sheldon enlists the help of Bernadette and Amy to overcome his fear of birds.

9 - The Boyfriend Complexity

Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.

9 - The Vengeance Formulation

After hes humiliated on National Public Radio, Sheldon vows to destroy Kripke, while Wolowitz tries not to destroy his new relationship with Bernadette.

9 - The White Asparagus Triangulation

Sheldon is thrilled when Leonard starts dating a woman who meets Sheldons stringent standards.

9 - The Cooper-Hofstadter Polarization

When theyre invited to present at a physics conference, Sheldons reluctance to share the credit leads to a tiff between him and Leonard, and Pennys intervention only exacerbates the situation.

9 - The Citation Negation

Sheldon and Amy are devastated after learning from a Russian paper that Super Asymmetry has already been discovered and disproven. Ultra-competitive Bernadette asks Stuarts girlfriend to teach her how to beat Howard in a popular video game.

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10 - The Confidence Erosion

Sheldon and Amy try to eliminate stress from wedding planning by applying math to the process. Also, Koothrappali “breaks up” with Wolowitz after realizing his best friend is actually hurting his confidence.

10 - The Property Division Collision

Sheldon and Leonard try to divvy up their shared belongings, but cant agree on anything. Also, Koothrappali and Stuart fight to be the most helpful during Bernadettes final weeks of pregnancy.

10 - The Earworm Reverberation

Sheldon has a revelation when he realizes why a song was stuck in his head. Also, Amy invites Dave over for dinner despite their previously awkward date, and Wolowitz and Koothrappali become obsessed with a fan of their band, Footprints on the Moon.

10 - The Discovery Dissipation

Leonard has to deal with the fallout of disproving Sheldons new scientific discovery. Raj spends a week at Howard and Bernadettes apartment.

10 - The Fish Guts Displacement

When Amy gets sick, Sheldon tries to nurse her back to health; Wolowitz and his father-in-law plan a fishing trip.

10 - The Flaming Spittoon Acquisition

When Stuart asks Amy out on a date, Sheldon must confront his feelings and consider where his relationship with Amy is going.

10 - The Alien Parasite Hypothesis

Amy finds she has sexual feelings for Pennys ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.

10 - The Gorilla Experiment

Penny gets help from Sheldon in order to understand what Leonards work is, while Wolowitz develops a jealousy when Leonard starts hanging out with his new girlfriend.

10 - The Vartabedian Conundrum

Leonard asks Penny for advice when his new relationship starts moving too fast.

10 - The Loobenfeld Decay

Leonard and Sheldon each lie to avoid seeing Pennys concert, but Sheldons is a bit too complicated for his own good.

10 - The VCR Illumination

Sheldon and Amy are still down about their theory being disproven, but a VHS tape from Sheldons past inspires him not to give up. Bernadette turns into a pageant mom when she tries to help Howard ace his Magic Castle audition.

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11 - The Birthday Synchronicity

Howard and Bernadette welcome their new baby and Sheldon and Amy celebrate Amys birthday.

11 - The Opening Night Excitation

After more than five years of dating, Sheldon and Amy spend their first night together. Also, Leonard, Wolowitz, and Koothrappali must decide who will take their extra Star Wars movie ticket.

11 - The Cooper Extraction

While Sheldon is at home in Texas, the rest of the gang realizes how much he has changed their lives as they decorate the apartment Christmas tree.

11 - The Santa Simulation

During a Dungeons and Dragons game, Sheldon revisits Christmas memories; Amy, Penny and Bernadette look for a date for Raj.

11 - The Speckerman Recurrence

Leonard must face his fears after being contacted by his high school tormentor.

11 - The Justice League Recombination

The guys find a super use for Pennys new boyfriend, Zack, when they enter a costume contest as the Justice League.

11 - The Maternal Congruence

A Christmas visit from his mother has Leonard discovering shes kept a lot of news from him that she shares with Sheldon and worrying if shell approve of his romance with Penny.

11 - The Bath Item Gift Hypothesis

Penny starts dating Leonards handsome colleague; Leonard and his friends are tortured by Sheldons obsession with gift-giving etiquette.

11 - The Pancake Batter Anomaly

With his friends knowing how sour he acts when sick—and avoiding him as a result—Sheldon is nursed by Penny, who hasnt a clue what shes in for.

11 - The Celebration Reverberation

Sheldon and Wolowitz plan birthday celebrations for Amy and Halley, respectively. Also, Leonard get a Christmas letter from his brother that causes him to spiral out about his own lack of accomplishments.

11 - The Paintball Scattering

Penny and Leonard organize a paintball game that results in mayhem when Sheldon is jealous of Amy. Also, Koothrappali catches Anu with her ex-boyfriend, and Stuart doesnt want to move in with Denise.

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12 - The Matrimonial Metric

Sheldon and Amy will try to use science to see who should be their Maid of Honor and Best Man.

12 - The Holiday Summation

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas.

12 - The Sales Call Sublimation

Penny gets more than she bargained for when Leonard agrees to meet with a psychiatrist on her behalf. Also, Sheldon and Koothrappali collaborate on an astronomical discovery, and Wolowitz and Bernadette cant believe what they are feeling after Stuart moves out.

12 - The Hesitation Ramification

When Pennys big acting break on NCIS is a bust, Leonard struggles to help her, which results in Penny asking Leonard a bold relationship question. Meanwhile, Raj and Stuart try to practice their social skills, and Sheldon navigates the intricacies of being funny.

12 - The Egg Salad Equivalency

When Sheldon is accused of sexual harassment, he ends up getting Raj, Leonard and Howard in trouble.

12 - The Shiny Trinket Maneuver

Sheldon gets in trouble with Amy when he isnt impressed by her recent accomplishment, and Howard must come to grips with Bernadettes dislike of children.

12 - The Bus Pants Utilization

Leonards idea for a smartphone app derails his friendship with Sheldon.

12 - The Psychic Vortex

Leonard is aghast to find out a secret of Pennys: she believes in psychics. Meanwhile, Sheldon tries to assist Koothrappali in picking up a girl at a university mixer.

12 - The Killer Robot Instability

Pennys criticism of Wolowitzs romantic life pushes him into depression and AWOL for a fighting robot battle the rest of guys are depending on him for.

12 - The Jerusalem Duality

With Sheldon rattled over meeting Dennis, a 15-year-old physicist whos smarter than he, Leonard helps him look for a way to debunk Denniss research.

12 - The Propagation Proposition

Pennys ex-boyfriend, Zack, and his wife want a baby, but when Zack is infertile, they ask Leonard for help. Also, Koothrappali attempts to mend things with his ex-fiancée, Anu.

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13 - The Solo Oscillation

When Sheldon kicks Amy out to work solo, she and Leonard bond during a series of science experiments. Also, Bert the geologist replaces Wolowitz in the band Footprints on the Moon, and Sheldon finds Penny a surprising source of scientific inspiration.

13 - The Romance Recalibration

When Penny feels that Leonard is taking her for granted, she decides to go on a spa weekend with Amy. Also, Wolowitz and Koothrappali try to fix a squeaky floorboard in the babys room.

13 - The Empathy Optimization

After having to deal with a sick Sheldon, Leonard, Penny and the gang try to treat themselves to a Sheldon-free weekend.

13 - The Occupation Recalibration

Sheldon tries to relax after he is forced to take a vacation. Meanwhile, Leonard struggles to be supportive of Penny after she quits her job, and Bernadette seeks Stuarts help in replacing one of Howards comic books. Also, Amy receives an unwanted attention from a co-worker.

13 - The Bakersfield Expedition

As the guys don costumes and go on a road trip to a comic book convention, the ladies decide to stay home and try to interpret a comic book.

13 - The Recombination Hypothesis

Leonard, who broke up with Priya, asks Penny out to a spur-of the-moment romantic dinner for two, and the duo contemplates on their relationship.

13 - The Love Car Displacement

Bernadette runs into her ex-boyfriend while attending a science event with Wolowitz.

13 - The Bozeman Reaction

When their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system.

13 - The Friendship Algorithm

Sheldon creates a scientific procedure for making friends.

13 - The Bat Jar Conjecture

Sheldon finds himself booted from the gangs Physics Bowl team and replaced with Leslie, so he forms his own team, hoping to prove hes superior.

13 - The Confirmation Polarization

Sheldon and Amy are thrilled when their super asymmetry theory is proven by two physicists, until they try to kick Amy off the Nobel nomination; Bernadette has a big success at work.

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14 - The Emotion Detection Automation

Sheldon beta-tests an MIT invention after hearing it can help him read peoples emotions. Also, Leonard cant hide his feelings when Penny announces her brother is coming to town, and Raj invites his ex-girlfriends over to give him dating advice.

14 - The Meemaw Materialization

Meemaw meets Amy, but it isnt all roses. Meemaw seems to have an axe to grind with her. Sheldon comes to Amys defense, but not before Meemaw lets a little secret of his slip.

14 - The Convention Conundrum

After the guys cant get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones. Meanwhile, the girls try to feel more mature by going to a fancy hotel for tea.

14 - The Cooper/Kripke Inversion

Sheldon faces a crisis of confidence when he is forced to work with his nemesis, Barry Kripke; Raj and Howard buy expensive action figures of themselves.

14 - The Beta Test Initiation

Leonard and Penny deal with the idea of starting a relationship again and Raj finally finds a woman he can talk to without being drunk, in the form of Siri on his new phone. Meanwhile, Sheldon decides to start a YouTube series entitled Sheldon Cooper presents Fun with Flags with the help of Amy.

14 - The Thespian Catalyst

Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friends girlfriend.

14 - The Einstein Approximation

Sheldons search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.

14 - The Financial Permeability

Sheldons solution to Pennys financial difficulty leads to a confrontation between Leonard and Pennys ex-boyfriend.

14 - The Nerdvana Annihilation

When delivery of another collectible leads to Pennys lashing out at Leonard, he decides its time to give up his habit, much to his friends protestation.

14 - The Separation Triangulation

Koothrappali finds himself in the middle of domestic drama when he learns the woman hes dating, has a very upset husband. Also, when Sheldon rents his old room back for a quiet place to work, he drives Leonard crazy by being a model tenant.

14 - The Meteorite Manifestation

Sheldon is thrilled to help Bernadette and Wolowitz navigate bureaucratic paperwork, until he discovers they are breaking the law. Also, Leonard is disappointed when his friends exclude him from a scientific project.

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15 - The Novelization Correlation

Leonards book raises questions, and Amy guest stars on the new Professor Proton show.

15 - The Locomotion Reverberation

Leonard and Wolowitz try to distract Sheldon when he slows the progress of their guidance system. Also, Penny and Amy take Bernadette out for the night, leaving Raj and Stuart to care for baby Halley.

15 - The Valentino Submergence

Sheldon and Amy host a live Valentines Day episode of Fun with Flags, Leonard and Penny grapple with getting older, Howard and Bernadette find a surprise in their hot tub and Raj is torn between Emily and the cute girl he met at the Comic Bookstore.

15 - The Locomotive Manipulation

Sheldon and Amy take a train ride to Napa Valley with Howard and Bernadette on Valentines Day. Leonard and Penny take Rajs dog to the vet when she accidentally eats some chocolate.

15 - The Spoiler Alert Segmentation

A fight between Sheldon and Leonard impacts Amy and Pennys living arrangements; while Howard is away, Raj helps Mrs. Wolowitz out.

15 - The Friendship Contraction

Sheldons selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.

15 - The Benefactor Factor

A wealthy donor to the university makes Leonard consider how far hes willing to go for the sake of science.

15 - The Large Hadron Collision

Leonard can only bring one guest on a trip to see CERNs Large Hadron Collider (the worlds largest and highest energy particle accelerator) in Switzerland on Valentines Day.

15 - The Maternal Capacitance

Leonard and Penny are drawn together after a disastrous visit from Leonards mother.

15 - The Pork Chop Indeterminacy

The rest of the gang fall for Sheldons twin sister, and Leonards plan to win her heart is derailed when Sheldon declares hell be the one to decide who can date her.

15 - The Donation Oscillation

Penny tries to seduce an abstaining Leonard to ruin his donation for her ex-boyfriend, Zack, and his wife, Marissa. Also, Wolowitz, Bernadette, Anu and Koothrappali turn Koothrappalis canceled bachelor party into a couples trip.

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16 - The Neonatal Nomenclature

When Bernadette wont go into labor, the gang tries different tactics to get things started. Howard confronts Bernadette after Amy accidentally reveals shes already chosen their sons name.

16 - The Allowance Evaporation

Sheldon and Amy have their first fight since moving in together, and Koothrappali is shocked at the realities of financial independence when he stops receiving support from his father.

16 - The Positive Negative Reaction

When the gang finds out about Bernadettes pregnancy, they celebrate by singing karaoke. Also, Bernadette is concerned when Wolowitz freaks out over her pregnancy announcement, and Wolowitz is convinced he must make more money to provide for the baby.

16 - The Table Polarization

Leonard buys a dining room table and it causes Sheldon to reevaluate the changes in his life. Meanwhile, Wolowitz is offered a chance to go back to space and Bernadette struggles with whether or not to encourage him.

16 - The Tangible Affection Proof

The guys search for a perfect Valentines Day gift for their significant others; Stuart and Raj host a lonely people party at the comic book store.

16 - The Vacation Solution

When Sheldon is forced to take his vacation, he goes to work with Amy in her neurobiology lab.

16 - The Cohabitation Formulation

As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Rajs sister.

16 - The Excelsior Acquisition

Sheldon winds up in traffic court when he gets a ticket because of Penny.

16 - The Cushion Saturation

A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.

16 - The Peanut Reaction

Penny wants to throw a surprise party for Leonard, but Sheldons indulgence at an electronics store throws her off-track.

16 - The D & D Vortex

The gang finds out Wil Wheaton hosts a celebrity Dungeons and Dragons game involving William Shatner, Joe Manganiello, Kareem Abdul-Jabbar and Kevin Smith. Deception and betrayal are the path to make it to the one open seat.

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17 - The Athenaeum Allocation

Leonard jumps through hoops to help secure the perfect wedding venue for Sheldon and Amy. Also, Bernadette and Wolowitz have a hard time deciding who should stay at home with the kids and who should go back to work.

17 - The Comic-Con Conundrum

With Koothrappali cut off from his fathers fortune, he appoints Sheldon to help him get out of debt. Also, Penny considers joining Leonard at Comic-Con.

17 - The Celebration Experimentation

After more than nine years together, the gang finally celebrates Sheldons birthday, surprising him with a special guest.

17 - The Friendship Turbulence

After arguing with Sheldon, Howard tries to make amends by taking him to NASA headquarters in Houston. Penny has second thoughts about quitting her waitressing job when her car dies. Amy gets involved in trying to find Raj a date.

17 - The Monster Isolation

After a bad date, Koothrappali decides to never leave his apartment; Pennys acting skills impress Sheldon.

17 - The Rothman Disintegration

Sheldon battles Kripke for a coveted office at the university. Penny receives a very unusual gift from Amy.

17 - The Toast Derivation

Sheldon becomes concerned when everybody begins to hang out at Rajs apartment and discovers Leonard is the center of the group.

17 - The Precious Fragmentation

When the guys find a ring from The Lord of the Rings at a garage sale, it threatens to tear them apart.

17 - The Terminator Decoupling

Leonard, Sheldon and Wolowitz are ecstatic to learn that a famous science-fiction actress (Summer Glau) is on board the train they are taking to San Francisco.

17 - The Tangerine Factor

Pennys break-up spurs Leonard to summon the courage to ask her out, and each goes to Sheldon for advice on their upcoming date.

17 - The Conference Valuation

When Penny and Bernadette go to San Diego for a pharmaceutical sales convention, Wolowitz is in charge of the kids. Also, Sheldon finds a book on experimenting on kids, and the guys plus Amy make a day of it.

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18 - The Gates Excitation

Bill Gates visits Pennys work, and the gang schemes to meet him. Hilarity ensues.

18 - The Escape Hatch Identification

When Raj moves out of his apartment, Leonard and Penny offer him Sheldons old room.

18 - The Application Deterioration

Leonard, Sheldon, and Wolowitz run into problems when they file for a patent for their infinite persistence gyroscope. Also, Penny, Amy and Bernadette give Koothrappali dating advice when Emily reaches out to him after their breakup.

18 - The Mommy Observation

When Sheldon visits his Mom in Houston, he is forced to confront a new reality. Meanwhile, Rajs Murder Mystery party starts some fights within the gang.

18 - The Contractual Obligation Implementation

Leonard, Sheldon and Howard give lectures on science to junior high students. The girls ditch work to go to Disneyland. Raj devises a date for Lucy that fixes their social anxiety problems.

18 - The Werewolf Transformation

Sheldon becomes agitated when his regular barber is out sick. Astronaut training causes Howard to reconsider wanting to go into space. Penny beats Leonard in chess, the first time she plays.

18 - The Prestidigitation Approximation

Sheldon is baffled by Wolowitzs magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.

18 - The Pants Alternative

Sheldons friends come to his aid when his fear of public speaking stands between him and a coveted award.

18 - The Work Song Nanocluster

Pennys home business turns into a complete nightmare when Sheldon takes over.

18 - The Laureate Accumulation

When competitors Pemberton and Campbell charm America on a publicity tour, Sheldon and Amy try to bring Nobel laureates Kip Thorne, George Smoot and Frances Arnold to their side. Also, Halleys fear of the dark leads to opportunity and conflict for Howard, Bernadette and Stuart.

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19 - The Tenant Disassociation

When Leonard learns Sheldon is the president of the tenants association, he decides to run against him. Also, Bernadette encourages Wolowitz and Koothrappali to find the owner of a drone after they find it in the backyard.

19 - The Collaboration Fluctuation

Leonard, Penny and Raj adjust to their new living arrangement, and Sheldon takes an interest in Amys work.

19 - The Solder Excursion Diversion

Amy is shocked at a revelation from Sheldon after she buys him a new laptop. Also, Koothrappali sells out Leonard and Wolowitz after they lie to their wives in order to attend an early screening of a movie.

19 - The Indecision Amalgamation

While Raj is wracked with guilt when he tries to date two women at once, Penny wrestles with whether to take a role in a cheesy movie and Sheldon is torn trying to choose between two gaming systems.

19 - The Closet Reconfiguration

Howard considers whether or not he should open a letter from his father; Penny and Leonard host a grown-up cocktail party.

19 - The Weekend Vortex

Sheldon must choose between joining Amy at her aunts birthday party or playing videogames all weekend with the guys.

19 - The Zarnecki Incursion

Sheldons online-game account is hacked by Todd Zarnecki, who then proceeds to steal all his items prompting the guys to go on a quest to retrieve them. Penny, Bernadette and Amy discuss how Penny groomed Leonard to be willing to try various things and more adventurous boyfriend... for some other woman — Priya.

19 - The Wheaton Recurrence

A fight between Leonard and Penny threatens their relationship, while Sheldon battles Wil Wheaton in bowling.

19 - The Dead Hooker Juxtaposition

Penny squares off with a new beautiful female neighbor who may become the buildings new Penny.

19 - The Inspiration Deprivation

The concept of what it would mean for women everywhere if Amy were to win a Nobel Prize causes Amy to have a meltdown. Also, Koothrappali and Wolowitz try to relive the good old days after Wolowitz buys a scooter that looks like the one he had years ago.

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20 - The Reclusive Potential

A brilliant but reclusive scientist, Doctor Wolcott, invites Sheldon to his cabin in the middle of nowhere, and Leonard, Raj and Howard go along for the trip. Also, Penny and Bernadette improvise after Amy doesnt like the tame bachelorette party they planned for her.

20 - The Recollection Dissipation

Sheldon pushes himself to the limit when he collaborates on projects with Leonard and Wolowitz as well as Amy on the same day. Also, Bernadette is nearing the end of her maternity leave and must return to work.

20 - The Big Bear Precipitation

Sheldon spills a secret of Leonards when the two take a weekend cabin trip with Penny and Amy. Also, when Koothrappali goes overboard with pregnancy gifts, Wolowitz and Bernadette must draw the line.

20 - The Relationship Diremption

Sheldon faces a personal crisis after deciding hes wasting his time with string theory. Meanwhile, a double date between Raj, Emily and the Wolowitzes ends in embarrassment for Howard.

20 - The Tenure Turbulence

The girls get involved when Leonard, Sheldon and Raj compete for tenure at the University.

20 - The Transporter Malfunction

Penny buys Leonard and Sheldon “Star Trek” collectibles as a thank-you, leading Sheldon to be haunted by Mr. Spock. Meanwhile, Raj decides he has met the “Future Mrs. Koothrappali” after his parents set him up on a date.

20 - The Herb Garden Germination

Sheldon and Amy decide to start several rumors about the others as a test. Meanwhile, Howard takes his relationship with Bernadette to even higher level.

20 - The Spaghetti Catalyst

When Leonard and Penny arent speaking, Sheldon goes to extremes to keep them both happy.

20 - The Hofstadter Isotope

A fellow comic book enthusiasts hitting on Penny leads to Leonard and Howard going to a bars Ladies Night.

20 - The Decision Reverberation

Koothrappali is worried people wont take him seriously in his own field after publishing a paper that suggests he may have discovered alien life. Also, Leonard wants to be the principal investigator on a plasma physics study.

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21 - The Comet Polarization

Sheldons comic book store experiences changes when writer Neil Gaiman puts Stuarts store on the map. Also, Koothrappali takes credit for Pennys astronomical discovery, and friendships are threatened.

21 - The Separation Agitation

Howard and Bernadette have a hard time leaving Halley in day care when Bernadette returns to work. Also, Bert introduces the gang to his new girlfriend, Rebecca.

21 - The Viewing Party Combustion

Everyone must choose sides when a small argument between Leonard and Sheldon erupts into a heated fight during a group get-together.

21 - The Anything Can Happen Recurrence

To prepare for a date with Emily, Howard acclimates Raj to horror movies. Penny and Sheldon are upset when they discover Amy and Bernadette lied to avoid hanging out with them.

21 - The Closure Alternative

Amy tries to help Sheldon get over his compulsive need for closure when one of his favorite TV shows is canceled; Raj discovers a secret about Lucy.

21 - The Hawking Excitation

When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

21 - The Agreement Dissection

When Leonard spends too much time in the shower with Priya, Sheldon charges Leonard with two violations of the roommate agreement. However, before he can get too far, Priya uses her skills as a lawyer to nullify the charges due to the agreements vague wording, much to Sheldons dismay. When the guys take advantage of Priyas skills in order to eat Greek food on pizza night, Sheldon goes to Penny, who invites him to a girls night out with Amy and Bernadette, which Sheldon agrees to after Penny mentions that they may be talking trash about Priya. After the girls drink some cocktails, they decide to take Sheldon dancing, which Sheldon reluctantly goes along with. After dancing, Sheldon takes an intoxicated Amy back to her apartment and as well as talking about Priya, meets a monkey who is addicted to smoking cigarettes. Amy tells Sheldon not to give in to Priyas law skills, before kissing him and going to her bathroom to vomit.

21 - The Plimpton Stimulation

Leonard and Sheldon compete for the attention of a famous female physicist.

21 - The Vegas Renormalization

Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas, and Sheldon becomes locked out of his apartment and must stay with Penny.

21 - The Plagiarism Schism

Kripke has proof that Dr. Pemberton plagiarized his thesis in college, and Sheldon and Amy arent sure if they should turn him in or not; Wolowitz learns that Bernadette wasnt the only waitress at the Cheesecake Factory who had a crush on him.

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22 - The Cognition Regeneration

Leonard isnt thrilled when Penny considers taking a new job offered by her ex-boyfriend, Zack.

22 - The Fermentation Bifurcation

The gang goes to a wine bar and runs into Pennys old boyfriend, Zack. Also, Bernadette gets stuck spending the evening with Sheldon when she cant go wine tasting with the group, and things dont go as planned when Koothrappali introduces his new girlfriend, Claire.

22 - The Proton Transmogrification

As the gang celebrates Star Wars Day, Sheldon has difficulty dealing with the recent death of Arthur Professor Proton Jeffries.

22 - The Proton Resurgence

Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform; Bernadette and Howard run into trouble while dog-sitting for Rajs pet.

22 - The Stag Convergence

After the guys throw Howard a bachelor party, Bernadette reconsiders marrying him after learning about his sexual history.

22 - The Wildebeest Implementation

Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.

22 - The Staircase Implementation

Leonard tells Penny about how he met Sheldon for the first time...and what happened to the elevator.

22 - The Classified Materials Turbulence

Pennys second date with Stuart sees her making a comment that gives Leonard new hope for a relationship with her. Wolowitz realizes theres a crucial error in a NASA project hes working on.

22 - The Monetary Insufficiency

Sheldon goes to Vegas to win money for science. Also, Penny and Bernadette take Amy wedding dress shopping, but her terrible choice entangles them in a web of lies.

22 - The Maternal Conclusion

Leonard is pleasantly surprised when Beverly comes to visit and shes genuinely kind to him, until he finds out the real reason shes there. Also, Denise and Stuart overstay their welcome at the Wolowitz house.

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23 - The Gyroscopic Collapse

After Leonard, Sheldon and Wolowitz celebrate the completion of the top secret air force project, they are met with an unpleasant surprise. Also, Amy is offered a summer position as a visiting researcher.

23 - The Line Substitution Solution

Sheldon hires Stuart to spend the day with Amy when hed rather go to a movie screening. Also, Leonards mother, Beverly, comes to town and Penny struggles to make a connection with her.

23 - The Gorilla Dissolution

A bad day causes Penny to reevaluate her life choices – including Leonard. Meanwhile, Howard and Bernadette struggle to care for Mrs. Wolowitz, and Raj gets relationship advice from Sheldon.

23 - The Love Spell Potential

A date between Raj and Lucy takes both of them out of their comfort zones. After a trip to Las Vegas goes awry, the girls join in on a Dungeons and Dragons game, which causes Amy and Sheldon to re-evaluate their relationship.

23 - The Launch Acceleration

When NASA moves up Howards mission, he must face his fears and Bernadettes dad, thus putting the wedding plans in jeopardy. Meanwhile, Leonard says something surprising to Penny in the bedroom.

23 - The Engagement Reaction

When Howard finally breaks the news to his mom that hes engaged to Bernadette, it lands her in the hospital.

23 - The Lunar Excitation

While Penny worries that dating Leonard has ruined her for normal guys, Wolowitz and Koothrappali search for Sheldons perfect match online.

23 - The Monopolar Expedition

The guys plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.

23 - The Sibling Realignment

When Sheldon learns that his mother wont attend his wedding unless he invites his brother, Georgie, he and Leonard travel to Texas to end a family feud. Also, the Wolowitz kids inadvertently infest Amy, Bernadette, Wolowitz and Koothrappali with pinkeye.

23 - The Change Constant / The Stockholm Syndrome

Sheldon and Amy await big news.

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24 - Unraveling the Mystery: A Big Bang Farewell

Johnny Galecki and Kaley Cuoco will lead fans on a trip down memory lane, sharing some of the best-kept backstage secrets and personal memories from the past 12 years.

24 - The Long Distance Dissonance

The gang is concerned when Sheldons former admirer, Dr. Ramona Nowitzki, resurfaces while Amy is away at Princeton.

24 - The Convergence Convergence

Chaos ensues when Leonards recently divorced parents, Alfred and Beverly, and Sheldons devoutly religious mother, Mary, come to town. Also, Wolowitz and Koothrappali think the government is out to get them when they are contacted about their guidance system.

24 - The Status Quo Combustion

Sheldon get upset about his career, the destruction of the comic book store and Leonard and Pennys future living arrangements. Howard and Bernadette cant keep hold of a caretaker for his mother. With his entire world changing around him, Sheldon considers a major move.

24 - The Bon Voyage Reaction

When Leonard receives an exciting opportunity to work overseas, Penny and Sheldon are thrown for a loop. Raj and Lucys relationship comes to a crossroad.

24 - The Countdown Reflection

The fifth season ends with Howard and Bernadette deciding to get married before his NASA mission, causing the gang to scurry into overdrive in an effort to stage the wedding. NASA astronaut Mike Massimino has a cameo as himself.

24 - The Roommate Transmogrification

When Bernadette receives her PhD, Wolowitz feels emasculated. Raj and Leonard swap places and Penny does something shes regrets.

24 - The Bow Tie Asymmetry

When Amys parents and Sheldons family arrive, everybody is focused to make sure all wedding arrangements go according to plan – everyone except the bride and groom.

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