Leonard: Penny is not the reason I did not pursue that idea.
Sheldon: Oh really? Since meeting her, what have been your greatest accomplishments?
Raj: Easy. Sleeping with Penny.
Howard: Getting Penny to go back out with him after she dumped him.
Raj: Tricking Penny into getting engaged.
Howard: And a few weeks ago he almost did a pull-up!

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: So you can never take it (the sweater) off?
Leonard: No.
Raj: Not even to sleep?
Leonard: No.
Howard: So you're just an idiot?
Leonard: It's called proving a point.
Howard: Is the point you're an idiot?

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a fork lift?

Sheldon: I know the real reason you never made progress with that idea. You thought of it September 22nd, 2007. Two days later, Penny moved in and so much blood rushed to your genitals, your brain became a ghost town.

Amy: But enough about Penny, let's talk about us. We're looking good.
Bernadette: We are.
Amy: Better than good. I mean look at you, your body's bangin'.
Bernadette: Amy!
Amy: Don't Amy me. We're always talking about how hot Penny is. Come on, scientist to scientist, how big are those hadron colliders?

Bernadette: Guess who won a hundred dollars playing craps?
Penny: That's a dollar.
Bernadette: Guess who wildly over-tipped a cocktail waitress?