A great thing to do with kids is to go to the Adventure Caverns in Glenwood Springs at the other end of the Roaring Fork Valley from Aspen. There are amazing caverns at the top of a hill accessible via a gondola and also lots of fun rides like the Alpine Coaster and a giant swing that swings out over the Colorado River. The girls we took went on this roller coaster time after time! It is the highest roller coaster in North America at 7160 feet!