Penny: So you want me to be a teacher's pet?
Bernadette: Couldn't hurt.
Leonard: I don't know. Who here has ever been hurt because they were the teacher's pet?
*Sheldon, Amy, Howard, Leonard and Raj raise their hands*

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?

Sheldon: The correct animal for inter-species super soldier is the koala. You would wind up with an army so cute, it couldn't be attacked.

Sheldon: You shot your spit in my mouth!
Howard: Is that gonna be on the test? Because I don't think I can do that again.

Leonard: Sheldon, I promise, your uvula does not have an STD.
Sheldon: Are you sure? It just doesn't feel as innocent as it used to.