Raj: Oh, you bought cookies?
Sheldon: Yes, fig newtons. I was going to ask which scientist both helped to discover calculus and had a famous cookie named after him. And then after someone said Newton, I was going to tell them they're wrong. The cookies are named after a town in Massachusetts. And then I'd throw the cookies away.

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.

Sheldon: The correct animal for inter-species super soldier is the koala. You would wind up with an army so cute, it couldn't be attacked.

Sheldon: You shot your spit in my mouth!
Howard: Is that gonna be on the test? Because I don't think I can do that again.

Leonard: Sheldon, I promise, your uvula does not have an STD.
Sheldon: Are you sure? It just doesn't feel as innocent as it used to.