Amy: How'd it go with Leonard?
Penny: I don't think he'll be making that mistake again.
Bernadette: Good.
Penny: So, I know this goes without saying, but if either of you tell Leonard you helped me rewrite this paper, I will beat you both with a bag of oranges.

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

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

Leonard: What am I supposed to do?
Penny: Err, keep your mouth off other women.

Leonard: I did a bad thing.
Sheldon: Does it affect me?
Leonard: No.
Sheldon: Then suffer in silence.

Stephen Hawking: What does Sheldon Cooper and a black hole have in common? They both suck.

Sheldon: Steven Hawking's a genius and he talks like a robot. It's everything I ever wanted in a friend.