Penny: Wait, wait, just to be clear, when you guys say spa, does that mean the same thing as when regular people say it?
Leonard: Pretty much. Except we keep our shirts on in the sauna.

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: What, I'm not hot enough for Angelina Jolie?
Raj: Id like to weigh in here: No.

Amy: Are you in the lanthanide series?
Sheldon: Amy, it's Penny's turn. Penny.
Penny: Uh, I dunno. Are you food?
Sheldon: That's not a apropos! We've already established I'm found on the Periodic Table.
Penny: Well, it's a table, right? I mean, why can't there be food on it?
Sheldon: I knew she wasn't lead car material.

Sheldon: Good morning everyone and welcome to "Science and Society". I'm Dr. Sheldon Cooper, BS, MS, MA, PhD and ScD. OMG, right?