Aspen is home to some of the most dedicated endurance athletes around, and the Audi Power of 4 Ski Mountaineering Race is right up their alley. This year's race begins on Saturday, February 28 at 6am in Snowmass Base Village. Participants will ski, hike or skin up all four mountains of Aspen Snowmass, gaining more than 12,000 vertical feet over the 25-mile course. If this sounds like your kind of fun, grab a partner and register at www.aspensnowmass.com.