Leonard: Sheldon, Canada is not going to invade California.
Sheldon: Yeah, really? You think those hippies in Washington and Oregon can stop them?

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Sheldon: I would have been here sooner but the bus kept stopping for other people to get on it.

Leonard: You call that a glow stick? *Pulls out a Lightsaber* That is a glow stick!

Penny: Sheldon, that's not what girlfriends are for. Although you don't use them for what they're for, so what do I know?