Haha, that Phoebe Cates scene...I remember in the special features where the guy who played the brother (what his name? In real life it was Judge something...Nelson?) said that the actress who played Phoebe was supposed to walk into the bathroom and act surprised, so they didn't tell her what the brother would be doing. Turns out, he was masturbating with a dildo. Needless to say, it sufficed enough to get a good scare out of her.
Also, in the poolroom scene, Mike Damone was also supposed to have some nudity. They cut that out to get away from an (as it was called then) "X" rating. Also, the part where Phoebe was teaching the other girl how to give a BJ in the cafeteria was originally supposed to be done with the two girls in a Hot Tub.