Say what you want about Downhill skiing. I have stood on the sidelines at a major turn at a World Cup Downhill race in Whistler, and was in total awe at how the skiers managed to negociate the turn at close to 100 kmH. The sound of the wind was what really got me. It sounded like a race car going by, but with the motor off. I was super impressed.
Ironman man may or may not be on the list. Keep in mind that as a sport becomes more popular and more people do it, the difficulty and challenge in the eyes of many decreases. I recall a few years ago Outside Magazine had an article on this very topic, and even then, before the big boom in Ironman races and participation, they were poo, pooing Ironman for not being that hard and reasonably doable(their words NOT mine)
Steve Fleck @stevefleck | Blog