Leonard: I could spend months up here just going through his math.
Raj: I think Sheldon might.
Howard: Great. Who's gonna tell Amy we lost her fiancee to a madman in the mountains? [Howard and Raj look at Leonard]
Leonard: Hey, I drove.

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.

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

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: Well, of course I'm worried about you, I want you to be safe.
Amy: And I want you to be safe.
Sheldon: I will be. I'll have my friends with me. If anything should go wrong, I can use them as human shields.

Sheldon: *knock knock knock* Dr. Wolcott? *knock knock knock* Dr. Wolcott? *knock knock knock* Dr. Wolcott? [sound of many locks clacking]
Howard: That's a lot of locks.
Leonard: Mm. That was a lot of knocks, they were made for each other.

Sheldon: Do you really know how to Riverdance?
Amy: You tell me.
Sheldon: I'm the only man you do that for.