Leonard: Our babies will be smart and beautiful.
Sheldon: Not to mention imaginary.

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.

Leonard: Our babies will be smart and beautiful.
Sheldon: Not to mention imaginary.

Penny: So, what do you guys do for fun around here?
Sheldon: Well, today we tried masturbating for money.

Sheldon: Um, Penny, that's where I sit.
Penny: So, sit next to me.
Sheldon: No, I sit there.
Penny: What's the difference?
Sheldon: "What's the difference"?
Leonard: Here we go.
Sheldon: In the winter that seat is close enough to the radiator to remain warm, and yet not so close as to cause perspiration. In the summer it's directly in the path of a cross breeze created by open windows, there and there. It faces the television at an angle that is neither direct, thus discouraging conversation, nor so far wide to create a parallax distortion. I could go on, but I think I've made my point.