Amy: We need to fabricate a tantalising piece of gossip.
Sheldon: And a second non-tantalising piece to use as a control.
Amy: Then we'll track its progress through our social group and interpret the results through the competing academic prisms of mimetic theory, algebraic gossip and epidemiology.
Sheldon: Look at you, getting me to engage in the Social Sciences. You're a vixen, Amy Farrah Fowler.

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.

Raj: Shut your ass!

Sheldon: If you don't mind, I'd like to stop listening to you and start talking.

Sheldon: I must say, Amy, pretending to have intercourse with you has given me a great deal of satisfaction.