Sheldon: (To the smoking monkey) You really are an ass.

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: Are you suggesting I play dirty?
Amy: Yes, dirty. Dirty, dirty, dirty. Which brings me to our next order of business. [kisses Sheldon]
Sheldon: Fascinating.
Amy: I hope you don't take what I'm about to do as a comment on what we just did. [runs to bathroom and vomits]

Sheldon: Ah, memory impairment; the free prize at the bottom of every vodka bottle.

Sheldon: The mean Indian lady tried to make me eat lamb.