Leonard: That's two proposals, one day. Sounds like someone wants to spend the rest of their life telling people how to spell the name Hofstadter.

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.

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?

Amy: I guess it must have been back when I was in the Girl Sprouts.
Bernadette: Girl Sprouts?
Amy: My mom made it up as an alternative to the Girl Scouts. She didn't want me selling cookies on some street corner like a whore.

Sheldon: I know why. You've come to me because you're my Obi-Wan.
Arthur: I'm not familiar with that. Is that an Internet?

Penny: Oh, I get it. Like C-3PO. ... What happened to me?