i race comes to mind when you think of how hard this sport is.. 1985 Paris Roubaix.. 172 started - 35 finished.. Rain - Hail - sleet - snow temps in the 20's and these guys are still in short sleeves. Can you say hard as nails.
http://www.youtube.com/watch?v=QvAdfqo43s0
http://www.youtube.com/watch?v=wm3-g7uWQ4Y