Because I like mountain-biking, and suck at it, this used to happen to me on a regular basis. Best time. Biking in the trails north of Pasadena, I decided that riding the brakes was for wimps, and therefore, did not. Picked up an amazing amount of speed, especially when I hit the fireroad, which is gravelled over. At one turn, completely lost control of the bike, and opted to dive rather than going 15 feet down with the bike (which I had to scramble down to collect) An hour later, walked into the cafeteria, dripping blood from hands, elbows, and knees, asked for doubles of everything, sat down outside, and ate. Then took a shower and picked all the gravel out. Still have tons of scars from that one. Scars are manly. Scars from athletic endeavors, brawls, and other stupid feats of manhood, especially.