Sheldon: To paraphrase T.S. Eliot, this is the way the word ends, not with a bang but with a nephew.

Sheldon: I feel like a teen heartthrob.

Amy: What about Supercuts?
Sheldon: I tried once. They do men and women's hair in the same room at the same time. It's like Sodom and Gomorrah with mousse.

Penny: You know, Sheldon, sometimes it's nice not knowing what's coming. I mean, look at me and Leonard. We went out, we broke up, now we're trying again. We don't know what's gonna happen.
Sheldon: Oh, please, everyone knows what's going to happen.

Leonard: Hang on, uh, uh, roommate agreement. Ha! Um, no hootenannies, sing-a-longs, or barbershop quartets after 10:00 p.m.

Penny: Sorry, Sheldon, I'll move out of your spot.
Sheldon: Why? My spot, your spot; what difference does it make?

Leonard: What are you gonna do first?
Sheldon: I don't know. I could do anything. All bets are off. The world is my oyster. *slams hand on table* I got it. I'm gonna put on my Tuesday pajamas tonight.

Barber: I can cut it for you.
Sheldon: You're not Mr. D'Onofrio. I get my hair cut by Mr. D'Onofrio. *to Leonard* Can you believe this guy?

Althea: Can I help you?
Sheldon: Yes. Do you have something I could use as a cape?
Althea: Oh, dear. Did we spit out our pills, slip out of the ninth floor, and go on a little adventure?

Penny: All right, Sheldon, this craziness has gone on long enough. Please come home so I can cut your hair.
Sheldon: Penny, you're not trained. You're not licensed. Most importantly, you don't have access to my haircut records.
Penny: All right, honey, look, we've known each other for a long time now, right? I've taken you to Disneyland, I kicked a bully in the nuts for you, I sing you Soft Kitty when you're sick. You even saw me naked once.
Leonard: I'm sorry. Uh, what?
Penny: It was a long story. Anyway, Sheldon, I promise I know what I'm doing. Please let me cut your hair.