Soldier Hollow was the site of the 2002 Olympic cross-country ski competition. In the summertime, this nicely-built trail system is available for mountain biking. There are about 12 miles of trails located in a semi-circle on the rolling hills west of Heber. Although the total altitude gain isn't great (around 300 feet), the up-and-down riding can add up to a substantial bit of vertical. Base altitude is 5800 feet. Trails are easier-intermediate in technical requirement.
Soldier Hollow is a fee area within a state park. There's no fee gate, but officially you should pay to ride (2007 = $3). And, you'll need to sign a waiver. Stop at the main lodge to register.