Raj: Sheldon's right. This guy, this guy's brilliant.
Howard: Yeah, I mean, he's a little kooky, but a mind that can reconceptualize time probably has a reason for keeping a jar of toenail clippings that we just don't understand.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Howard: I invented a game. Want to play?
Leonard: Sure.
Howard: It's called Emily or Cinnamon. I give you actual quotes I've heard Raj say, and you guess if he was talking to his girlfriend or his dog.

Bernadette: Does your mother call you every day at work to see if you had a healthy lunch?
Howard: My mother calls me every day at work to see if I had a healthy bowel movement.

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