Sheldon: There's something I need to tell you.
Leonard: Okay.
Sheldon: I can't tell you.
Leonard: Why?
Sheldon: I can't tell you why I can't tell you. So I guess there's two things I can't tell you.
Leonard: I wish there were more.

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: 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.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Sheldon: If you're going to replace Wolowitz, I need to know a little bit more about you.
Stuart: All right.
Sheldon: Wolowitz went to MIT. What's your educational background?
Stuart: I went to art school.
Sheldon: Equally ridiculous. Let's go.

Sheldon: Settle down there, fake Wolowitz. No one likes a kiss-up.

Sheldon: Penny, please don't hurt my friend.