Sheldon: Look at the organizational chart. You're clearly listed as founder.
Leonard: Well, yes, and you're listed as Chief Executive Officer, Chief Financial Officer and Chief Operating Officer.
Sheldon: You missed Chief Science Officer, Chairman of the Board, and Head of the Secret Santa Committee.

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: I'm not saying that all senior citizens that can't master technology should be publicly flogged. But, if we made an example of one or two it might give the others incentive to try harder.

Raj: Ooh, Leonard is going all alpha nerd on Sheldon's ass.

Leonard: I had a great idea. Do you know how we're always having to stop and solve differential equations, like when you're doing Fourier equations or using the Schroedinger equation?
Sheldon: Howard doesn't, he's only an engineer.