Sheldon: Given the reaction to my costume, this party is a scathing indictment of the American educational system.
Kurt: You're a zebra, right?
Sheldon: (to Leonard) Yet another child left behind.

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: Homo habilis discovering his opposable thumbs says what?
Kurt: What?

Leonard: I call Frodo!
Sheldon, Raj, and Howard: Damn!

Leonard: We all have other costumes, we can change.
Raj: Or we could walk right behind each other all night. It'll look like one person going really fast.