Leonard: Homo habilis discovering his opposable thumbs says what?
Kurt: What?
Wolowitz: Check out the sexy nurse. I believe it's time for me to turn my head and cough.
Penny: Why can't all guys be like you?
Leonard: Because if all guys were like me the human race couldn't survive.
Leonard: That's right! Cuz' that's how we roll in the Shire!
Sheldon: Given the reaction to my costume, this party is a scathing indictment of the American educational system.
Kurt: You're a zebra, right?
Sheldon: (aside, to Leonard) Yet another child left behind ...
Wolowitz: Gentlemen, to the sewing machines!
Leonard: What's that?
Sheldon: Tea. When people are upset, the cultural convention is to bring them hot beverages. (a pause as he tries to think of what to do next, then he says awkwardly) 'There, there'. (another pause) You wanna talk about it?
Leonard: No.
Sheldon: Good! 'There there' was really all I had.
Leonard: If he [Penny's boyfriend, Kurt] were any bigger, he'd have moons orbiting him.
Sheldon: Oh,SNAP.
Sheldon: I don't care if anybody gets it. I'm going as the Doppler effect. If I have to, I can demonstrate. NYEEEROOOOM
Girl: What are you?
Sheldon: I'm gonna give you a hand: weawww.
Girl: A Choo choo train?
Sheldon: Clouse! weawwww
Girl: A brain damaged choo choo train?
Penny: Boy, you're really smart.
Leonard: Yeah, I'm a freaking genius.
Kurt: You are lucky little dwarf.
Sheldon: He is a hobbit! Don't worry, I've got your back!
Sheldon: I don't care if anybody gets it. I'm going as the Doppler Effect.
(Leonard, Sheldon, Raj, and Howard are all dressed as the Flash and they are deciding who will be what.)
Leonard: I call Frodo!
Sheldon, Raj, and Howard: (together) Damn!