Sheldon: Can I invite you in for tea?
Professor Proton: No, I really have to run .
*Penny walks in the room*
Penny: Hey Arthur, how are you?
Professor Proton: Well I guess one cup wouldn't hurt.

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?

Professor Proton: Oh, great, this again.

Professor Proton: Why isn't it ever Angie Dickinson's bedroom?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

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: (Talking about Howard & Raj) They are going to have sex before Sheldon and I do. I knew it!