Forget sleep. For many mountain bikers, nothing beats the rush of a 24-hour race. Up-all-night contests have boomed in popularity--about 35 are now held every year from New England to California, with more popping up overseas. The races have a festival atmosphere, with camping, music, bonfires and prizes for the best costumes. And you don't need to be as fit as Lance Armstrong to participate: most riders are weekend pedal pushers on teams that vie to finish the most laps. The Super Bowl of all-nighters is held annually in Moab, Utah (Oct. 16-17), where competitors race through desert canyon lands (grannygear.com). Colorado's 24 Hours of Steamboat (rockypeakproductions.com) features a course that descends through wildflower meadows. Or head for Italy's Finale Ligure, where vendors cook up huge pasta feasts (24hfinale.com). For more, see 24hoursofadrenaline.com.