Forget shuffleboard and dress-up dinners. The cruise industry is charting a new course in 2007, aiming for a younger market of adrenaline junkies, singles, and activity-loving families. Shore excursions are getting a closer look, too, since passengers don't want to get stuck on a tour bus or in a straw market—they want to go off-roading in the backwoods or partying with the locals. We've found nine trips that appeal to the young and the young-at-heart while still offering everything that makes cruising so great: You only have to unpack once, someone else does the driving (and they know the route), and each morning you wake up in a new and exciting destination.