Penny: Why can't all guys be like you?
Leonard: Because if all guys were like me the human race couldn't survive.

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.

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: 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.

Leonard: Homo habilis discovering his opposable thumbs says what?
Kurt: What?

Leonard: I call Frodo!
Sheldon, Raj, and Howard: Damn!

Leonard: We all have other costumes, we can change.
Raj: Or we could walk right behind each other all night. It'll look like one person going really fast.