LMAO - When I was younger, I jumped off a 20 foot stair case with a 55 gallon contractor's bag strapped to my ass. THAT was not fun. Later, I learned that you fall a good distance before the bag will actually create any drag... I had intended to try it from a much higher place, but my Father explained the laws of Mortality to me, and I decided I'd rather learn about physics in books than first hand.
I have flown off a house on a sheet of OSB, though. Roofing in the wind isn't really safe.