Go Kart Racing
Back in the day, my best friend Tommy, got bit by the racing bug.  He decided to buy one of those go karts and race it on the weekends.  A race track was set up at Kadena Air Base, Okinawa and we found ourselves watching every weekend.  This wasn't no Briggs and stratton.  A Yamaha 100cc motor powered this little beast and 35 to 40 mph was normal.  For anyone who thinks that you can't overturn one of these things I will tell you that it can be done.  Tommy scared the hell out of us when he ended up under the cart after a roll in turn 3.
Tommy
John