Leonard: Sheldon, we both agreed to do this.
Sheldon: It's a waste of time. I might as well explain thermodynamics to a bunch of Labradoodles.
Leonard: If you don't do this, I won't take you to the comic book store.

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: Isn't there a policy against dating graduate students?
Leonard: No, if you can talk to them, you can ask them out.
Raj: Damn, there's always a catch.

Penny: Whats Sheldon's deal? Is it girls, guys, sock puppets?
Howard: We operate on the assumption that Sheldon has no deal. Though we have many theories about how he might reproduce. I'm an advocate of mitosis.
Penny: What?
Howard: I believe that one day Sheldon will eat an enormous amount of Thai food and spilt into two Sheldons.

Penny: Holy crap on a cracker!