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

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.

Leonard: She didn't dump me. We were just in different places in the relationship.
Sheldon: I fail to see how a relationship can have the qualities of a geographical location.
Wolowitz: It's very simple. Leonard was living in a little town called "Please don't leave me", while Penny had just moved to the island of "Bye-bye!"

Leonard: Relax, it's just a dirty sock.
Sheldon: How on earth can you say "dirty sock" and "relax" in the same sentence?

Zack: Is that the laser? It's bitchin'.
Sheldon: Yes. In 1917, when Albert Einstein established the theoretic foundation for the laser in his paper "Zur Quantentheorie der Strahlung", his fondest hope was that the resultant device be bitchin'.
Zack: Well, mission accomplished!

(Sheldon notices Penny taking Leonard to his bedroom)
Sheldon: What's going on?
Penny: Get your noise-cancelling headphones, 'cause it's gonna get loud.
Sheldon: Oh, not this again.

Sheldon: Incidentally, one can get beaten up in school simply by referring to oneself as one.

Penny: Damn you, you rat bastard! In the olden days, I never would have known he was that stupid.

Sheldon: As a native Texan, I must say I've never heard the phrase "yeeehaw" used in quite that context.

Sheldon: Hello, Amy Farrah Fowler. I'm sorry to inform you that you've been taken in by unsupportable mathematics designed to prey upon the gullible and the lonely. Additionally, I am being blackmailed with a hidden dirty sock.
Amy: If that was slang, I'm unfamiliar with it. If it was literal, I share your aversion to soiled hosiery.

Amy: I don't object to the concept of a deity, but I'm baffled by the notion of one that takes attendance.

Sheldon: I should've brought an umbrella.
Leonard: What for? It's not going to rain.
Sheldon: I know that, but with skin as fair as mine, moon burn is a real possibility.
Howard: That's a bazinga, right?
Sheldon: One of my best, don't you think?

Leonard: Think about what this represents. The fact that we can do this is the only way of definitively proving that there are man-made objects on the moon, put there by a member of a species that only 60 years before had just invented the airplane.
Zack: What species is that?

Zack: Hey, I want to see this laser thing.
Penny: Oh, but what about the party?
Zack: It's a surprise party, doesn't matter when we get there.

Zack: How can you bounce a laser off the moon if there's no gravity?