Howard: Nice to see that the gals are getting along.
Leonard: Gals? Who are you, Fred Flintstone?

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.

Raj: She didn't even get to see my penis.

Sheldon: There's no need to interact with me. I'm just here to observe.

Penny: I'm sorry, shoes, but you have to go back.
Shoebox (Penny): But, Penny, we love you.
Penny: I love you, too, but you cost more than my rent.
Shoebox (Penny): But Penny, you look so good in us.
Penny: (To Amy) Damn it, the shoes are right!