"Uphilling" - walking or skinning uphill on skis - is a tremendously popular activity here in Aspen. And March's America's Uphill is the granddaddy of uphill racing: a 2.5 mile, 3000-foot + vertical hike up the front of Aspen Mountain. If this is your kind of fun and you'll be in town, you're in luck. You can register up until 4pm today, March 11, at Aspen's Ute Mountaineer store.