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The Big Bang Theory Season 4

"The Roommate Transmogrification"

Raj moves in with Sheldon on the fourth season finale of The Big Bang Theory. This takes Penny by surprise.

"The Engagement Reaction"

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

"The Wildebeest Implementation"

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

"The Agreement Dissection"

When Priya uses her lawyer skills to pick apart the roommate agreement, the girls take Sheldon dancing on this episode of TBBT.

"The Herb Garden Germination"

Sheldon and Amy spread gossip this week. Elsewhere, Howard takes a big step in his relationship with Bernadette.

"The Zarnecki Incursion"

Someone has the gall to hack into Sheldon's online game account this week. The guy go on a search to find out who would dare do such a thing.

"The Prestidigitation Approximation"

Wolowitz baffles Sheldon this week with a magic trick. Elsewhere, Leonard realizes that there's a problem with him dating Priya.

"The Toast Derivation"

Sheldon struggles with a realization on this episode: Leonard who is actually the center of the social group.

"The Cohabitation Formulation"

Wolowitz considers going all the way with Bernadette this week. Elsewhere, Leonard rekindles his relationship with Raj's sister.

"The Benefactor Factor"

A donor is willing to give Leonard a lot of money this week. In exchange for sex from him, that is.

"The Thespian Catalyst"

Sheldon gets acting lessons from Penny on this episode. Elsewhere, Koothrappali fantasizes about his best friend's gal.

"The Love Car Displacement"

There's tension at a hotel this week. That's because the group runs into Bernadette's ex-boyfriend during a science event.

"The Bus Pants Utilization"

Leonard gets an idea for a smart phone application on this episode. How does that go? Find out now.

"The Justice League Recombination"

The guys find a use for Penny's boyfriend this week, as they enter a costume contest and they go as the Justice League members.

"The Alien Parasite Hypothesis"

Amy realizes she has sexual feelings for Penny's ex on this episode. That's awkward. Meanwhile, Koothrappali and Wolowitz attempt to prove who would be the better superhero.

"The Boyfriend Complexity"

Penny asks Leonard to fib to her father this week. Elsewhere, Howard, Raj and Bernadette go for an all-nighter with a telescope.

"The 21-Second Excitation"

Wil Wheaton is back this week! He causes problems for the guys when they try to see a movie. Elsewhere, Penny and Bernadette invite Amy to a sleepover.

"The Apology Insufficiency"

Sheldon places Wolowitz's security clearance in danger this week. How so? By answering questions from an agent played by Eliza Dushku.

"The Irish Pub Formulation"

A major secret abounds this week, as Leonard keeps quiet about an affair with Raj's sister. Will Sheldon keep the secret?

"The Desperation Emanation"

Amy wants to introduce Sheldon to her mother on this episode. Meanwhile, Leonard is down on himself as he comes to terms with the fact that all the other guys have girlfriends.

"The Hot Troll Deviation"

We learn of an embarrassing secret about Wolowitz this week. How is that for a tease?!? Read our recap to learn more.

"The Zazzy Substitution"

The focus of this week's episode: Sheldon's search for an alternative to human companionship. Read on to see how that goes.

"The Cruciferous Vegetable Amplification"

By the time he downloads his consciousness into a robot body, Sheldon realizes he'll be long gone. As a result, he attempts to make himself live longer.

"The Robotic Manipulation"

Penny tags along for Sheldon's first date on the fourth season premiere. Elsewhere, Wolowitz discovers a new use for a robotic arm.

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