Mining roads from the late 19th and early 20th century make Crested Butte an awesome destination for off-roading, dirt bikes, and ATVs. Many roads will take you over 12,000 foot mountain passes and through historical camps. Be sure to check road conditions in advance to avoid getting turned around by snow drifts and downed trees.
A couple of great options to consider include Taylor Park, The highest concentration of trails in the area. And Pearl Pass via Brush Creek, which will take you to Aspen through wildflowers, boulder fields, and steep climbs. Guides and rentals are available as well: