I almost went like that when I was bout 12 years old. I aint kidding either. Me and coupla others was prowling pasture one day, was going cross top of tall steep pasture and spotted old tractor tire on top. Some young asshole mentoned getting inside it at top of hill and rolling to bottom. Naturally, I volunteered. (again, hold my beer and watch this shit). We stood it up, I got in cockpit (actually, middle of tire). I realized what bad judgement it was about 30 feet or so going down hill, I think I had started to achieve terminal velocity, realized I had no brake pedal inside tire, some asshole must have left that part on former tractor. As I was not wearing a G-suit at the time, I began to lose conciousness, wasnt even halfway down hill yet. I hit what they told me later was a small stump, and achieved liftoff, however, we had neglected to balance tire properly and instead of rolling when I came down, it was more of a tumble, at wich point I was happily ejected, or either I pulled ejection lever and punched out, kinda fuzzy at this point. Anyway, I was glad to be rid of tire, and finish getting all that vomit outa my mouth,,,randyp