Pre-season training for skiing doesn't have to be just boring weights and running on treadmills. That's why most of the SKI office spend late summer, autumn, and even early winter on two wheels riding dirt trails. Mountain biking can improve cardio, strengthen leg muscles, and hone quick-thinking maneuvers in tight spaces, all of which translates nicely into skiing. Best of all, ski areas are catching on to how much skiers love mountain biking and are building extensive trail networks for both cross country and downhill riding. These are some of our favorites, and definitely some of the best spots to spend time waiting for winter.