Liam displays his dark side to Naomi, who is stunned but captivated by the intense, handsome bad-boy. Meanwhile, Annie and Ethan face another bump in their relationship when Adrianna makes it known that Ethan and Rhonda shared a kiss. Also, Silver and Dixon make a film that stirs quite a ...

Penny feels threatened when another sexy woman moves into the apartment building and angered when she senses the guys are being taken advantage of.

Chelsea's discovery of naked pictures of another woman on Charlie's iPhone leads to his swapping stories of sexual experiences during a drunken night with Alan, Herb, and Jerome.

Jack plans a perfect party for his 50th birthday, but finds it pales to a birthday party of his youth. Liz is tasked to make Tracy think he's going for a trip on a space shuttle. Dennis Duffy tries to make amends to Liz because he has a sex addiction—a ...

Liz finds out Drew's good looks afford him special treatment from society. Jenna hopes a new hairdo will keep her in the public eye. With Tracy's contract up for renewal, Jack tries to keep him at TGS.

Penny's business selling hair accessories out of her apartment gets out of hand when an over-caffeinated Sheldon takes charge.

Chelsea's illness gives Charlie a chance to prove he can take care of her, but also yearning to run away from the situation.

Jacks seeks a name for a new mini-microwave that the Legal Department will allow. Liz can't find a way out of jury duty and is forced to leave the staff unmanaged. Tracy sees being able to afford FCC fines as license to swear on television. Jenna gets medication to let ...

The gang is thrilled when they see Terminator: The Sarah Connor Chronicles' Summer Glau is also aboard their train to San Francisco for a scientific symposium. Meanwhile, Sheldon frets over having forgotten a paper he wants to present to George Smoot.

Charlie's admission that he's in love with Chelsea gets a surprising reaction from her.