Leonard: Can we please talk about something else? Maybe something vaguely related to life as we know it on this planet?
Howard: Okay, how about this for a topic, why is Leonard being a giant douche? Assuming giant douches are possible.
Sheldon: Of course they are. Leonard's being one.

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: You did this, didn't you?
Wil Wheaton: Come on, Sheldon, do you really think I'd break up a couple just to win a bowling game?
Sheldon: No, I suppose not.
Wil Wheaton: Good. Keep thinking that.
Sheldon: Wheeeeatoooon!

Sheldon: Well, well, well, if it isn't Wil Wheaton. The Green Goblin to my Spider-Man, the Pope Paul V to my Galileo, the Internet Explorer to my Firefox!

Sheldon: I am the ball, my thoughts are its thoughts, its holes are my holes.