Penny: What exactly do you think goes on here?
Sheldon: Well, conversations that you wouldn't be comfortable having in front of the opposite sex. You know, who has the best cervix. Which sanitary napkin is all the rage right now. Men's buttocks and how you want to pat and squeeze them.

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.

Howard: I invented a game. Want to play?
Leonard: Sure.
Howard: It's called Emily or Cinnamon. I give you actual quotes I've heard Raj say, and you guess if he was talking to his girlfriend or his dog.

Penny: I love him, but if he's broken, let's not get a new one.

Penny: Shouldn't you be getting ready for work?
Sheldon: I'm not going. Would you like to know why?
Penny: You're sad about not getting any thing done last night, so you're gonna sit around and pout about it.
Sheldon: Boy, I'm not nearly as mysterious as I think I am.