The Capital Off Road Pathfinders (CORP) are the Madison/Dane County mountain biking club - http://www.madcitydirt.org/
CORP created trails in six areas around Madison - Blue Mounds State Park, Middleton Bike Park, Badger Prairie, Cam-Rock, Quarry Ridge, and The Farm. They also organize several endurance races and events throughout the year, including the 12 hours of Blue Mound and the Twelve Hours Pitch Black Singletrack at Cam-Rock County Park.
Blue Mound State Park is 25 miles west of Madison, Wisconsin, and is one of the best open spaces in the area for trail running, mountain biking, and running on singletrack and doubletrack. The park is out Highway 151 from Madison.
There are miles of trails, and more added all the time. You can make a 15-20 mile loop on the trails without a lot of repeats. Unlike a lot of Wisconsin trail, this is technical, not just dirt roads or cross-country ski trail.
The park is home to the Blue Mound Trail Run in June, and the 12 Hours of Blue Mound Mountain Bike Race in August.
There is a swimming pool in the park for cooling off after your adventure.
Mountain Bike Races and Rides: