One of my favorite trail races in the area. Really well coordinated, low key, and a range of distances for all skill levels. Events include 10K, half, full, 50K and 50M. Devil's Lake State Park is a beautiful area and the view from the top of the bluff mid-race is amazing.
Be prepared for a lot of elevation, but a lot of beer waiting for you at the finish. You can either camp out the night before or stay at the nearby Devil's Head Resort. Any questions, ask me (Matt J) -- I've run it twice and camped out both times.
Full details here: http://dwd.runningfitsites.com/devilslake-home