The Colorado Rockies, Denver's National League baseball team, play April-October in Coors Field (2001 Blake St., LoDo. 303/292-0200 or 800/388-7625. www.coloradorockies.com). Because of high altitude and thin air, the park is among the hardest in the major leagues for pitchers -- and the Rockies have had a tough time preserving young arms. But each year they manage to finish on a high enough note to bring the fans back into the stands the next season.