The Big Bang Theory

Penny finds herself along for the ride on Sheldon's first date ever. Meanwhile, Wolowitz finds a new use for a robotic arm.

When Sheldon realizes he won't live long enough to download his consciousness into a robot body, he attempts to extend his lifespan. Apple Co-Founder STEVE WOZNIAK guest stars.

Sheldon and Amy (MAYIM BIALIK) break up.

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work. KATEE SACKHOFF and GEORGE TAKEI guest star as Wolowitz's love gurus.

Amy wants Sheldon to meet her mother.

A visit from Raj's sister creates tension among the guys.

ELIZA DUSHKU guest stars as an FBI Agent.

When the guys camp in line for a screening, their plans are thwarted by Sheldon's greatest nemesis, WIL WHEATON (guest starring as himself).

Penny pulls Leonard into a lie when her dad comes to visit.

Sheldon's girlfriend is attracted to another man.

Penny's new boyfriend wants to hang out with the guys.

Leonard and Sheldon fight for control of a project.

Tension runs high when everyone is staying at the same hotel for a science event and Wolowitz worries he can't measure up to Bernadette's ex-boyfriend (guest star RICK FOX).

Sheldon takes acting lessons from Penny.

A wealthy donor to the university (guest star JESSICA WALTER) makes Leonard consider how far he's willing to go for the sake of science.

As Howard contemplates taking things with Bernadette to the next level, he must choose between his girlfriend and his mother. Leonard rekindles his relationship with Raj's sister.

Sheldon decides to get a new group of friends.

Leonard's girlfriend asks him to stop seeing Penny.

Sheldon's online gaming character gets robbed.

Gossip spreads like wildfire - thanks to Sheldon & Amy.

Leonard's girlfriend puts Sheldon in his place.

Raj attempts to solve his problem with talking to women.

Howard finally tells his mom he's marrying Bernadette.

After hearing Leonard and Priya indulge in a Star Trek bedroom fantasy, Raj moves in with Sheldon on the fourth season finale.