Sheldon: *knock knock knock* Leonard? (x3)
Leonard: What, Sheldon!? What, Sheldon!? What, Sheldon!?
Sheldon: Tell me what you see here.
Leonard: The blunt instrument that will be the focus of my murder trial?

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 ask you to find some way to suppress your libido.
Penny: I could think about you.
Sheldon: Whatever works.

Raj: Ooo.
Penny: What's the matter, Lassie? Did Timmy fall down the well?

Sheldon: Well, this is very pleasant.
Leonard: I'm glad you're enjoying yourself.
Sheldon: And you said there would never be enough pasta for the three of us.