Raj: Zack, this is my friend Claire.
Zack: You're hot. You seeing anybody?
Raj: Uh, she's seeing me.
Zack: Why'd you say she's your friend?
Raj: We're just keeping it casual.
Zack: Why is he being casual with you? You seem great.
Claire: I don't know. Ask him.
Zack: Why are you being casual with her? She seems great.

Zack: So what's your invention?
Howard: Well, we're using quantum vortices to replace gyroscopes in guidance systems.
Leonard: What's neat is that they can maintain angular momentum indefinitely.
Zack: Angular momentum. I was wondering about that.

Zack: Okay, I'm ready. I'm Zack, and I'm, uh ... oh, crap, why is this so hard?

Zack: Look up in the sky. Its a bird. Its a plane. I forget the rest.

Zack: My gluteus what?

Zack: Hey, Penny, how's it going?
Penny: Hey, Zack, what are you doing here?
Zack: My dad's company prints the menus for this place. I'm just dropping off some new ones, laminated. Makes 'em easier to clean if people throw up on 'em. Guess how I got the idea?
Penny: Yeah, I got it, I got it.

Zack: It's my fault. I was a terrible husband. I was never around.

Zack: So, long story short, I nailed her.
Sheldon: When he finished, he shouted Eureka!
Zack: No, I always shout, Holy Moly! Don't know why. Just do.

Zack: Penny?
Penny: Oh, Zack, hi. You guys remember Zack?
Howard: Yeah, hey, buddy.
Amy: Hello.
Raj: Hey.
Zack: Hey, did you two get married?
Penny: We did.
Leonard: Yeah, mmm-hmm.
Zack: To each other?
Penny: Yes.
Zack: Cool. 'cause other than when you broke up with him and dated me, then broke up with me, and then dated me one more time before going back to him, I was always rooting for you two.

Zack: Boy, you get some dirty looks over there when you ask for ice.

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.

Leonard: So, how'd you two guys meet?
Zack: My company designs the menus for the Cheesecake Factory.
Leonard: Your company?
Zack: Well, it's my dad's, but me and my sister are VPs.
Leonard: So, menus?
Zack: I know it sounds easy but there's a lot of science that goes in designing them.

Howard: You could put it in a satellite or a rocket, and it'll run forever.
Zack: Cool. Could it be used for missiles and war stuff?
Howard: Yeah, but we didn't create it for weapons.
Leonard: And I doubt the military would be interested in our little guidance system.
Zack: Is it better than the one they use now?
Howard: A lot.
Leonard: Way better.
Zack: Huh. You sure you guys are smart?

Penny: Yeah, lying isn't my favorite part of the job. Actually, I'm not crazy about a lot of it.
Zack: Hey, if you're not happy there, I've been looking for a new head of sales at my company. And we don't sell drugs, just menus, so the only lie you'll be telling is we print on recycled paper. We don't.

Zack: Do you have a bodyguard to keep spies away?
Leonard: I have Sheldon, that keeps most people away.
Zack: I miss that guy. He's like the Swedish Chef Muppet. I don't know what he's saying, but he's funny.
Leonard: Oh, I know what he's saying, and he's not, he's not funny.