The mountain and lake vistas, high-altitude climbing, and long technical descents of this up-and-coming biking mecca in the Sierra Nevada are ideal for intermediate riders looking to improve their technique. Test your skills on the Downieville Downhill's Sunshine Trail, a 1.3-mile introduction that links to the more established Bucher Ranch trail. Full-face helmets are recommended for the gnarly 15-mile, 4,000-foot descent. [$95 for shuttle service and a rental bike; downievilleoutfitters.com]