Just incredible fun... the climb up the intial hill is hard going but it pays back in a big way. There is some superb downhill through rock gardens, serene trails through aspen stands (and look out for the bearclaw marks on the bark), flowing singletrack across open hills. It's got a bit of everything. The descent to the junction with Canal Trail is gripping but watch out for the sting in the tail...
from Crested Butte follow the New Deli trail out to South Crested Butte, only a couple of miles; then follow the county road (Brush Creek Road) out past the trailhead to Cold Spring Ranch, about 2 miles; there is a right turn up a fairly steep hill, approx 1/2 mile beyond Cold Spring Ranch; on completing the trail you end up on this county road, follow it back to South CB and then CB itself
http://www.singletracks.com/item.php?c=1&i=1056