Sheldon: How are those nipples feeling, chief?

Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

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

Penny: If you guys were hungry, why didn't you order something at the restaurant?
Bernadette: We did. You never brought it.
Penny: Oh, that's right. Nachos and a turkey club.
Amy: Not even close.
Penny: Well, I was too busy standing up for my friend to worry about your ... I want to say salmon.
Amy: You want to say sorry.

Howard: So you can never take it (the sweater) off?
Leonard: No.
Raj: Not even to sleep?
Leonard: No.
Howard: So you're just an idiot?
Leonard: It's called proving a point.
Howard: Is the point you're an idiot?