Howard: I guess it was pretty smart using our quantum technology as the basis for a communication system.
Leonard: Be even better if he swapped out the helium for xenon.
Howard: Ooh. So instead of having to keep it at negative 271 degrees, you'd only have to keep it at negative 108. It would be way more efficient.
Leonard: And xenon has a bigger nucleus, so coherence would make it an easier signal to see.
Howard: You're brilliant!
Leonard: We should tell Sheldon.
Howard: You're an idiot! We don't tell Sheldon. We go to the military behind his back and we screw him like he screwed us.
Leonard: All right, you're right, you're right, we don't need him. We can do this all on our own.
Howard: Do you think you can do the math?
Leonard: No. But if someone else does it, I can double check the crap out of it.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Howard: Why would the military want Sheldon?
Leonard: I don't know. Target practice?

Barry Kripke: Whoa, whoa, whoa. You didn't tell me we were doing this just to stick it to Sheldon.
Leonard: Well-
Barry Kripke: I messing with you. This sundae just got a cherry on top!

Sheldon: And worse than that, Edison filmed the first on-screen kiss, so he's basically a pornographer. Although every time I put that in Wikipedia, someone takes it out.