Penny: Trust me, this is the right thing.
Leonard: I know. And it's not like we're abandoning him.
Plus, we can FaceTime him whenever we want, you know, once iPhones are invented in his universe.

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?

Howard: You know what's really happening here? Your girlfriend is breaking up our band.
Raj: She has nothing to do with this. I am my own man.
Howard: Oh, please. Your brain belongs to whoever's willing to sleep with you.
Raj: That is so not true.
Howard: Really? Remember when you were gonna get circumcised for Rachel Bernstein?
Raj: That had nothing to do with Rachel. It was an overreaction to a bad zipper injury.

Howard: What kind of music are you thinking of?
Stuart: I like all kinds of music, but my favorite genre is free.

Howard: I don't need this. I'm quitting the band!
Raj: Fine, I quit, too!
Howard: Then get out of my house!
Raj: With pleasure!
*door slams*
*Howard sighs*
Howard: Raj, wait!
Raj: What took you so long?