Leonard: We're always the good guys. In D&D, we're lawful good. In City of Heroes, we're the heroes. In Grand Theft Auto, we pay the prostitutes promptly and never hit them with a bat.
Sheldon: Those women are prostitutes? You said they were raising money for stem cell research.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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

Raj: But excuse me, I have something to say. None of you may realize it, but I was very much looking forward to this weekend. It was gonna be like the old days -- the four of us hanging out, playing video games, before you guys all got girlfriends. Do you have any idea what it's like to be the only one without a girlfriend? Even if I get one someday, I'll still be the guy who got a girl after Sheldon Cooper!

Leonard: We'll miss you Sheldon.
Sheldon: Yeah, well, who wants to spend the whole weekend, running around a bunch of pretend planets, battling made up monsters? That's for babies.
Howard: Yeah, but it's got lightsabers.
Sheldon: Please, Amy! It's got lightsabers!

Howard: Look, if you don't want to go to the party, just don't go. You're a grown man. Act like one. Tell Amy you want to spend the weekend having a sleepover and playing video games with your friends!