Raj: What are you drawing over there?
Sheldon: It's a hypothetical containment field for a Frisbee-sized wormhole that could serve as a portal to a parallel universe.
Howard: Oh, you silly doodlebug.
Leonard: You know, a lot of scientists believe that making contact with other life-forms would probably not end well for us.
Sheldon: It's a Frisbee-sized wormhole, Leonard. You can block it with a Frisbee. Calm down.

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 may not realize it, but I have difficulty navigating certain aspects of daily life. You know, understanding sarcasm, feigning interest in others, not talking about trains as much as I want. It's exhausting!

Sheldon: (Playing hackey sack) One, two, three, four, five, six, seven, eight. Drat. I'm never going to get to forty-three again. One, two, three, four. Rats.

Penny: Hey! Shouldn't you be out with your gang spray painting equations on the sides of buildings?