Sheldon: Well, Leonard, you know, who should keep this? On the one hand, I love Mr. Spock more than you do. On the other hand, I care more about clocks than you do.
Leonard: So you think you should keep it?
Sheldon: I'll be right across the hall. You'll probably be able to hear it.
Leonard: Keep the clock, Sheldon.
Penny: Thank you.
Amy: Thank you?

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.

Sheldon: It's not my fault I'm bad at sharing; I skipped kindergarten.

Sheldon: If it's like your 3-D chess game, then you're out of your length, width and depth. Amy, get the Neosporin, somebody just got burned.

Raj: Hey, this pregnancy had an emotionally-needy third wheel way before you came along.