some of the best riding on the front range, mix of singletrack, fireroad, as much technical as you want, as much uphill as you want....and down !
http://www.larimer.org/naturalresources/htmp.cfm
Horsetooth Mountain Park<br />Take Harmony west toward the mountain, go throught hte front range hills<br />5 miles on the right, the parking lot is there
http://www.singletracks.com/item.php?c=1&i=1561