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Raj moves in with Sheldon on the fourth season finale of The Big Bang Theory. This takes Penny by surprise.
When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.
Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.
When Priya uses her lawyer skills to pick apart the roommate agreement, the girls take Sheldon dancing on this episode of TBBT.
Sheldon and Amy spread gossip this week. Elsewhere, Howard takes a big step in his relationship with Bernadette.
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.
Wolowitz baffles Sheldon this week with a magic trick. Elsewhere, Leonard realizes that there's a problem with him dating Priya.
Sheldon struggles with a realization on this episode: Leonard who is actually the center of the social group.
Wolowitz considers going all the way with Bernadette this week. Elsewhere, Leonard rekindles his relationship with Raj's sister.
A donor is willing to give Leonard a lot of money this week. In exchange for sex from him, that is.
Sheldon gets acting lessons from Penny on this episode. Elsewhere, Koothrappali fantasizes about his best friend's gal.
There's tension at a hotel this week. That's because the group runs into Bernadette's ex-boyfriend during a science event.
Leonard gets an idea for a smart phone application on this episode. How does that go? Find out now.
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.
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.
Penny asks Leonard to fib to her father this week. Elsewhere, Howard, Raj and Bernadette go for an all-nighter with a telescope.
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.
Sheldon places Wolowitz's security clearance in danger this week. How so? By answering questions from an agent played by Eliza Dushku.
A major secret abounds this week, as Leonard keeps quiet about an affair with Raj's sister. Will Sheldon keep the secret?
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.
We learn of an embarrassing secret about Wolowitz this week. How is that for a tease?!? Read our recap to learn more.
The focus of this week's episode: Sheldon's search for an alternative to human companionship. Read on to see how that goes.
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.
Penny tags along for Sheldon's first date on the fourth season premiere. Elsewhere, Wolowitz discovers a new use for a robotic arm.