Amy: Okay, so how do you feel about party balloons?
Sheldon: Uh, Mylar balloons, yes. Latex balloons, no. Water balloons, I will jump off the roof and aim for your car.

Leonard: Can I get his contact info?
Stuart: Sure, uh, but just so you know, he's kind of a diva.
Leonard: He is?
Stuart: Oh, yeah. Won't take the bus. He won't pack his own lunch. Won't let you spend the night on his couch.

Bernadette: What kind of cake do you like?
Sheldon: Well, my favorite is chocolate with strawberry frosting, three layers, and if there's writing on it, make sure it's not all caps. I don't need my dessert yelling at me.

Leonard: Hey, uh, you know, he told a sad story about how his sister tricked him into thinking Batman was coming to his party.
Howard: That's funny. Let's do that.

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: Very well. You may celebrate my life by throwing a party with cake, presents and a shower of admiration and love. But then you owe me big-time.

Penny: You know, if you had a party now, you have plenty of friends that would love to come.
Leonard: And we live here, so we have no choice.
Penny: Yeah.

Amy: You realize none of those things would happen now?
Sheldon: I do, but why do you care if I celebrate my birthday at all?
Amy: Well, you made my last birthday so memorable, I wanted to return the favor.

Amy: Can you please just tell me why?
Sheldon: Fine. As you know, I have a twin sister with whom I obviously share a birthday. Every year we'd have a party. No one I invited would ever come, because they didn't like me.
Amy: I'm sorry.
Sheldon: Oh, that part wasn't so bad. I didn't like them, either. But then I'd inevitably spend the whole day being tortured by my sister's friends.
Penny: Oh, you poor thing.
Sheldon: When I was six, they told me Batman was coming to my party. I waited by the door for hours. Closest thing to Batman I saw was when a robin flew into the window.

Amy: But it's the one day a year that's just all about you.
Leonard: One day. (Laughs) Right.

Penny: Yeah, what is the problem? Is it about getting older?
Sheldon: Please! Look at this porcelain skin. I'm like a human sink.

Penny: Well, where is he?
Amy: Sheldon?
Leonard: I'll check his room.
Sheldon: Surprise!
Penny: Oh, my God!
Sheldon: Just one example of how birthdays can be terrible. Now, can we please drop this subject and pick a new one? Yeah, I suggest "how thick can a soup get before it becomes a stew?" You know, the answer, it may surprise you.

Penny: Wait a minute. You mention his birthday and he vanishes?
Leonard: Well, where's that information been this whole time?

Sheldon: What is it?
Amy: Well, your birthday's coming up and you've never let us celebrate it. And I was hoping maybe this year we could.
Sheldon: Oh, I suppose that's a discussion we could have. (Sheldon runs back up the stairs)
Amy: Okay, great, I mean, it doesn't have to be a big party or anything. I was just - Where'd he go?

Amy: So Sheldon, there's something I've been wanting to talk about but I know it's kind of a touchy subject.
Leonard: Way to narrow it down to everything.