Ross: You don't believe in gravity? Phoebe: Well, it's not so much that, you know, like, I don't believe in it, you know, it's just ... I don't know, lately I get the feeling that I'm not so much being pulled down as I am being pushed! (Knocking on the door) Chandler: Uh oh. It's Isaac Newton, and he's pissed. Quick Pheebs, jump on the ceiling!