This place has one of the biggest Fat Tire Festivals anywhere. It has steep single for those who want the more gnarly approach. It also has nice access roads for those who just want to get a nice ride in. If you're a die-hard, you can ride to the top. However, there is the lift if you don't want the 3000+ vertical.
How to get there:
The good stuff is on the back side of Vail Mountain. The trails are all marked.