Sheldon: I remember the song! It's called "Darlin'" by the Beach Boys! Oh, thank goodness! I'm not crazy! I don't have to take a pigeon as my bride!
Leonard: There goes our shot at him living on the roof.

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: 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.

Howard: Don't feel bad. Some day someone will be throwing out your work, too.
Leonard: That someone was Sheldon and the day was yesterday.

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?

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. We are made of particles that have existed since the moment the universe began. I like to think those atoms traveled fourteen billion years through time and space to create us, so that we could be together and make each other whole.

Wil Wheaton: You know that the movie actually has a little bit of a cult following.
Penny: Really?
Wil Wheaton: Yeah. I was at a science-fiction convention, and I saw a woman dressed as your half-ape character.
Leonard: Oh, if she was with an Indian guy dressed like a banana, that was just my friends, Howard and Raj.

Sheldon: I've changed. Like the frog who's put in a pot of water that's heated so gradually, he doesn't realize he's boiling to death.
Penny: Or you're the frog who's been kissed by the princess and turned into a prince.
Leonard: Or you're just a tall, annoying frog.

Leonard: We're here to see Koothrappali, not kill Batman.

Sheldon: I like it. I think you're on to something.
Leonard: Really? You're not messing with me?
Sheldon: Not at all. In fact, I have got something for just such an occasion. I was starting to think I'd never get a chance to give it to you. Good job!
Leonard: You're giving me a sticker?
Sheldon: Not just a sticker. That's a sticker of a kitty saying "Mee-wow".
Leonard: I'm not a preschooler.
Sheldon: Fine, I'll take it back.
Leonard: I earned this. Back off.

Leonard: Well, you can spend the rest of the day being bitter about this--
Sheldon: Agreed.
Leonard: I was going to say "or," but why bother?

Leonard: You know what, this bottle was meant to celebrate an achievement. Let's make a pact. When one of us gets their first big breakthrough, we'll celebrate by opening this bottle and toasting Professor Abbott.
Howard: I love that.
Raj: Me too.
Leonard: Then, of course, rubbing our success in Sheldon's face.
Howard: Well that's the best part.

Wolowitz: Raj, did you ever tell your sister about the time Sheldon got punched by Bill Gates?
Priya: Oh, God, you're kidding.
Raj: No, Gates gave a speech at the university. Sheldon went up to him afterwards and said, "Maybe if you weren't so distracted by sick children in Africa you could have put a little more thought into Windows Vista."
Leonard: Bam, right in the nose. Made me proud to own a PC.

Leonard: Oh, I know. This might help. *Gets a ring out of his wallet*
Penny: Where did you get a ring?
Leonard: I've had it for a couple of years. Not important. Penny, will you marry me?
Penny: Oh, my God, yes.
Leonard: This would have been so much more romantic if you didn't have monkey hair on your finger.