Mountain Biking - Lebanon Hills, Theodore Wirth and Mammoth
I first mountain biked while living in Chile, South America. When I returned to Minnesota, I thought that, without mountains, there'd be no "real" mountain biking. I was very mistaken. There are great trails around the Twin Cities themselves, with obstacles and a maze of trails varying in difficulty. There are many trails around Duluth and the rest of the state as well. Check with Minnesota Off-Road Cyclists [MORC (http://www.morcmtb.org/)] about trails where you want to ride. Spin those wheels and have some fun!