Zack: Oh, man, I didn't mean to do that. But I do appreciate you recognizing my swimmer's body. Which, incidentally, I got from playing Marco Polo at the YMCA.

Zack: One question. How can you be sure it won't blow up?
Leonard: The laser?
Zack: The moon.

Zack: Whoa, you dated Penny?
Leonard: She didn't tell you?
Zack: She told me she dated a guy named Leonard. Who would have thought it was you?
Leonard: Who else would it be?
Zack: I don't know. Somebody bigger and- Yeah, sure. Why not you?

Leonard: Don't worry about the moon. We, we set our laser to stun.
Zack: Smart.
Leonard: Now, we'll be able to see the beam when it leaves, but it won't be strong enough when it comes back to be seen by the naked eye.
Zack: (chuckling) Naked.

Sheldon: Well, it makes perfect sense. Because you're an expectant mother, you can't drink alcohol. I don't like to. You can't have sushi. I don't like to. You can't go in hot tubs. I consider them vats of sweaty people soup.
Bernadette: Gee, Sheldon, I dont know.
Sheldon: Oh, come on. Roller coasters, caffeine, runny eggs, I've been avoiding these things all my life. And now, because you're pregnant, you have to.

Leonard: Hey, did you ever think about the military applications for the guidance system?
Sheldon: Of course.
Leonard: Does it bother you?
Sheldon: No, it did at first. But then I talked it through with Frank and Alicia, and they really helped put things into perspective.
Leonard: Who are these people?
Sheldon: Leonard, friends are like toilet paper. It's good to have extras under the sink.

Raj: Hey, dude, you're killing me with Claire.
Zack: What are you talking about?
Raj: I mean, come on, look at you. You're classically handsome, you've got a swimmer's body. Next to you, I look like me.