Penny: He's such an angel when he's asleep.
Leonard: Yeah. Shame he has to wake up.
Penny: I think we can do it.
Leonard: Smother Sheldon in his sleep? Wouldn't that be wrong?

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.

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

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.

Raj: Hey, Leonard?
Leonard: Yeah?
Raj: I haven't had sex in a year.
Leonard: Where are you going with this, Raj?
Raj: Don't flatter yourself, dude.

Leonard: Hey, where've you been?
Sheldon: I was talking with Penny.
Howard: What's wrong with you? You can't hang out with your roommate's ex. That's totally uncool.
Leonard: No, it's fine. I don't care. I'm over it.
Raj: Yeah, he's over it; that's why he's been whining all day about trying to invent that memory-wiper gizmo from Men in Black.
Sheldon: Is he making any progress? Because I'd like to erase Ben Affleck as Daredevil.
Howard: So would Ben Affleck.

Penny: So, how've you been?
Sheldon: Well, my existence is a continuum, so I've been what I am at each point in the implied time period.