Leonard: That's two proposals, one day. Sounds like someone wants to spend the rest of their life telling people how to spell the name Hofstadter.

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.

Amy: I guess it must have been back when I was in the Girl Sprouts.
Bernadette: Girl Sprouts?
Amy: My mom made it up as an alternative to the Girl Scouts. She didn't want me selling cookies on some street corner like a whore.

Sheldon: I know why. You've come to me because you're my Obi-Wan.
Arthur: I'm not familiar with that. Is that an Internet?

Penny: Oh, I get it. Like C-3PO. ... What happened to me?