Rafting from Moab, Utah down the Colorado River is a family vacation worth going out of your way for.  There are several outfitters in Moab that do and outstanding job. Tagalong Expeditions, www.tagalong.com , and Red River Adventures offer trips from one to five nights on the river with all your meals and gear provided.  Rafting is approriate for kids as young as 5 and is one of the rare activities that can be enjoyed by teenagers and their parents, if they can get past the lack of indoor plumbing for a few days.  The whitewater is exciting enough to keep everyone from getting bored but not so exciting that you feel in danger, safety is a priority with the guides, with dinner a close second.  Bring a waterproof camera, this is a once in a lifetime experience.