Leonard: I'm gonna have sex with you right here, right now, on that washing machine.
Penny: No, you're not.
Leonard: Come on, please.
Penny: If you want to do something, you can help me fold this sheet.
Leonard: Folding a sheet in my underwear, still pretty crazy.

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: 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.

Professor Proton: Can I ask you a question?
Leonard: Yeah, sure.
Professor Proton: Why do you put up with Sheldon?
Leonard: Oh, you know because we're friends.
Professor Proton: Why?
Leonard: Wow, you ask really hard questions. Look, I know he can be aggravating, but what you have to remember is he's not doing it on purpose, it's just how he is. But he's also loyal and trustworthy and we have fun together.
Professor Proton: You know you're describing a dog?
Leonard: He did bite me once. But in his defense, I came up behind him while he was eating.
Professor Proton: They hate that.
Leonard: Sheldon is the smartest person I have met. He's a little broken and he needs me. And I guess I need him too.
Professor Proton: Why is that?
Leonard: Boy, you will not let this go, will you?

Barry Kripke: Yes, yes, yes. He's a jolly good fellow. What time do the strippers arrive?

Stuart: Okay, I'll go. Howard, when I think about you and Bernadette starting this wonderful life together, I can't help but get a little choked up. I mean, look at you. You have everything. Look at me. I'm 37. I sleep in the back of a comic book store, and I have the bone density of an 80-year-old man. To Howard.

Raj: When I moved to America I was pretty lonely, but when I met Howard my life changed because we could be lonely together.