Take a good look around you, gals: Little boys never truly grow up. Sure, they morph and mutate, but in the end, they all still want to play with big trucks. New Zealander Ed Mumm of Steamboat Springs wasn't any different, but he turned his stunted childhood fantasy into a big idea, opening what is probably the nation's (if not the world's) first heavy-equipment theme park. For a fee, Mumm will put willing grownups into the driver's seat of a bona fide excavator or bulldozer for a half- or full-day romp in the sandbox, complete with orientation, instruction and special activities. Open year-round (in winter, participants can push snow; after it melts, there's a fantabulous dirt pile), Dig This is like primal therapy, only better.