Episode Guide
The Zarnecki Incursion
Season 4, Ep. 19
When Sheldon has his World of Warcraft account hacked and his character stolen from, the guys team up to discover out who did it. Meanwhile, Bernadette and Amy try to help Penny deal with Leonard's continuing relationship with Priya.
View Gallery ►The Prestidigitation Approximation
Season 4, Ep. 18
Sheldon is baffled by Wolowitz's magic trick. Meanwhile, Priya disapproves of Leonard continuing to be friends with Penny.
View Gallery ►The Toast Derivation
Season 4, Ep. 17
Told Leonard is the center of the gang and miffed that they've started hanging out at Raj's, Sheldon seeks to form a new group of friends of which he can be the center.
View Gallery ►The Cohabitation Formulation
Season 4, Ep. 16
Bernadette tells Howard that it's time to choose between moving in with her or staying with his mother. Leonard discovers Raj's sister Priya is back in town and reconnects with her, and Amy tries to comfort Penny when she finds out.
View Gallery ►The Benefactor Factor
Season 3, Ep. 15
After meeting at a fundraising gala, an aged, but wealthy, Caltech donor makes Leonard ponder if he's willing to have sex with her to secure another donation.
The Thespian Catalyst
Season 4, Ep. 14
Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about Bernadette.
View Gallery ►The Love Car Displacement
Season 4, Ep. 13
A science convention at a hotel leads to Bernadette running into an ex-boyfriend and Wolowitz worrying he can't quite compare.
View Gallery ►The Bus Pants Utilization
Season 4, Ep. 12
Their friendship becomes strained when Sheldon tries to take over Leonard's creation of a smartphone application that solves differential equations.
The Justice League Recombination
Season 4, Ep. 11
The guys get Zack and Penny to join their Justice League costume for a New Year's Eve bash at the comic book store.
View Gallery ►The Alien Parasite Hypothesis
Season 4, Ep. 10
Amy crushes on one of Penny's dim ex-boyfriends, Zack. Raj and Wolowitz argue over who'd be the better superhero.
View Gallery ►The Boyfriend Complexity
Season 4, Ep. 9
When Penny's father visits, she gets Leonard to pretend to still be her boyfriend. Meanwhile, Howard, Raj, and Bernadette spend the night on an astronomy project.
View Gallery ►The 21-Second Excitation
Season 4, Ep. 8
The guys camp out in line to see a print of Raiders of the Lost Ark with 21 extra seconds and are outraged to see Wil Wheaton and his friends being allowed to skip the line. Penny and Bernadette invite Amy to their girls night.
The Apology Insufficiency
Season 4, Ep. 7
The rest of the gang is interviewed by the FBI for Wolowitz's security clearance, with Sheldon accidentally letting slip some damaging information.
View Gallery ►The Irish Pub Formulation
Season 4, Ep. 6
When Raj's sister has a one-day layover he forbids the others from hooking up with her, unaware she and Leonard already did long ago.
The Desperation Emanation
Season 4, Ep. 5
Leonard is depressed to realize all the other guys have girlfriends, while he doesn't. Amy wants to introduce Sheldon to her mother.
View Gallery ►The Hot Troll Deviation
Season 4, Ep. 4
Wolowitz tries to get back together with Bernadette. Sheldon and Raj go to war at the university.
View Gallery ►The Zazzy Substitution
Season 4, Ep. 3
When Sheldon "breaks up" with Amy, the guys worry when he starts replacing her with cats.
View Gallery ►The Cruciferous Vegetable Amplification
Season 4, Ep. 2
Sheldon calculates that he'll be dead before technology exists to download his consciousness into a robot, so he goes on a binge of healthy living and ultra-safety.
View Gallery ►The Robotic Manipulation
Season 4, Ep. 1
Howard uses a robotic arm for his own pleasure. Penny assists Sheldon with his first date.
View Gallery ►The Lunar Excitation
Season 3, Ep. 23
Howard and Raj try to find the perfect match for Sheldon by setting him up on an Internet dating site. Seeing her moronic new boyfriend interact with the gang makes it abundantly clear to Penny that she can't go back to dating stereotypical dumb jocks after dating Leonard.
View Gallery ►The Staircase Implementation
Season 3, Ep. 22
A squabble over the thermostat setting leads to Leonard going over to Penny's and recounting for her the story of how he met and moved in with Sheldon.
View Gallery ►The Plimpton Stimulation
Season 3, Ep. 21
Sheldon hosts a visiting female physicist, but her intelligence seems matched by her libido.
View Gallery ►The Spaghetti Catalyst
Season 3, Ep. 20
Subsequent to Leonard and Penny's break-up, Sheldon tries to hide from Leonard and the gang that he had a friendly spaghetti dinner at Penny's.
The Wheaton Recurrence
Season 3, Ep. 19
Sheldon gets to square off on the bowling alley against nemesis Wil Wheaton. Meanwhile, Leonard's miffed when Penny doesn't respond the way he hoped after saying, "I love you."
View Gallery ►The Pants Alternative
Season 3, Ep. 18
Sheldon's fear of speaking in front of large groups threatens his ability to accept an award, so the gang tries to help him get ready for the big night.
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