Leonard: (to Penny) It upsets Sheldon when you play with the Sheldon.

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.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Penny: Look, can we just forget about this extra stuff and can you just tell me what Leonard does?
Sheldon: Alright. Leonard is attempting to learn why subatomic particles move the way they do.
Penny: Really? That's it? Well, that doesn't sound so complicated.
Sheldon: It's not. That's why Leonard does it.

Howard: Hey, ma, can I have lamb stew for dinner?
Mrs. Wolowitz: Lamb stew? I'd have to go to the supermarket.
Howard: Please? I got a real hankering.
Mrs. Wolowitz: Oh, I can't say no to my little tushie face. I'll be back soon.