Ever heard of raccoons climbing on a roof?

Question:When I come home to my parents house during the summer, I wake up 3-4 times a week to the something walking on the roof. It's always too dark to see what it is, but it seems to be about the size of a raccoon (rather large). My bed is next to my window, and one night last year I woke up to this thing sitting in my window, literally staring at me. I wound open the window, and it even hit it and the thing didn't budge. I yelled, clapped, hit the screen...and ended up having to get a flashlight and almost crawled on the roof from another window before I finally scared it off. Any suggestions for preventing it from coming back up here? My window is in the front of my house, so I don't think putting a big trap on the roof would be very attractive. There are big trees right next to the roof, so I imagine it might be crawling up those trees and onto the roof, but I'm not sure. I've also woke(n?) up to the sound of animals fighting (or mating?), possibly coming from directly below my window

Answers:
Oh yes, we had them climb up on our house when we lived on a farm. They are very destructive, and will dig through the roof to get in. We had them make holes behind dormer windows and get in. We set traps on the roof to catch them, because on the ground we would catch cats!! I can't tell you how to keep them off. Do you live on a farm, where there are lots of things for them to eat?? You can catch them pretty easily with traps and tuna, cat food, little debbie oatmeal cookies, and pepsi. Unfortunately, then you have to dispose of them once they are caught!