Leonard: Can you be more specific on how my eyebrows are "stupid"? No, never mind. It's right here.

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?

Howard: [Chuckles] Look at that. There's finally a woman in your life you can talk to.

Sheldon: Now, today's episode of 'Fun with Flags' is not fun, but it is important. Flags: You gotta know how to hold 'em, you gotta know how to fold 'em.

Leonard: I missed you.
Penny: You see me all the time. You sure you don't just miss the sex?
Leonard: Well, yeah, the sex with you is pretty great. Have you ever tried it?
Penny: I have. You're not wrong.