Sheldon: So your mirth is merely a discharge of nervous energy with no semantic content at all?
Penny: My mirth. Classic.
Sheldon: Is there a station coming up where I can board your giggling train of thought?
Penny: It's not a big deal, Sheldon. It's just, ever since Leonard's been dating Raj's sister, I've had to keep my distance. I don't get to hear all your jibber-jabber.

Penny: At one point, they had me figure out how to get a banana out of a puzzle box.
Leonard: Wait, Sheldon gave me a banana in a box. He was testing me, too.
Penny: Unbelievable.
Leonard: And how could a chimp even solve that? That was impossible.
Penny: Really? You couldn't get it out?

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Howard: Hell hound.
Raj: Who let the satanic dogs out?

Raj: Sheldon, that's my water.
Sheldon: Oh, dear Lord!
Leonard: That's not your water.
Raj: I know.

Priya: What happened?
Bernadette: Howard's mother had a heart attack because I have sex with him and she can't.