Howard: Wait till you see this.
Raj: It's fantastic. Unbelievable!
Leonard: See what?
Howard: (Putting in DVD) It's a Stephen Hawking lecture from MIT in 1974.
Leonard: This isn't a good time.
Howard: (Imitating Stephen Hawking) It's before he became a creepy computer voice.

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.

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

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Leonard: Our babies will be smart and beautiful.
Sheldon: Not to mention imaginary.

Penny: So, what do you guys do for fun around here?
Sheldon: Well, today we tried masturbating for money.

Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really!
Sheldon: If the height of a step is off by as little as two millimeters, most people will trip.
Leonard: I don't care. 2 millime--? That doesn't seem right.
Sheldon: It's true. I did a series of experiments when I was 12. My father broke his clavicle.
Leonard: Is that why they sent you to boarding school?
Sheldon: No. That was the result of my work with lasers.