Howard: You have any idea what you're getting Sheldon for his birthday?
Raj: He's been fascinated with dinosaurs lately. Maybe we could get him a fossil.
Leonard: Well, just don't get anything Jurassic. He feels like that whole chunk of time has gone Hollywood.

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?

Penny: So what's going on?
Sheldon: I don't know. I looked around the room, and I saw all the faces and the presents, and it it was just too much.
Penny: I get that. Hey, you want to just bring a few people in here? You know, Wil Wheaton in the bathtub, Batman on the toilet. It'll be like the weirdest Comic-Con ever.

Leslie Winkle: Uh, in the past, I would've said something obnoxious, like, "Happy birthday, dumbass". But I'm not gonna do it. You and I have both grown a lot, and it's just so nice to see you all again. So happy birthday, Sheldon.
Sheldon: Oh. Oh, now, you know I hate change. Say it.
Leslie Winkle: Happy birthday, dumbass!

Amy: We've got someone who couldn't be here but really wanted to wish you a happy birthday.
Stephen Hawking: Hello, Sheldon.
Sheldon: (gasps) Professor Hawking.
Stephen Hawking: Happy birthday to you.
Sheldon: Thank you so much. I can't believe you're-
Stephen Hawking: Happy birthday to you.
Sheldon: Oh, you're singing. Well, I'm sorry.
Stephen Hawking: Happy birthday, dear Sheldon.
Leonard: Uh, Professor Hawking, if you just give us one second, we'll light the candles, and we can all sing together.
Stephen Hawking: I was crushing it, but all right.