You've already got both a car and an SUV that can magically transform into watercraft at the touch of a button, but what to do about your spoiled kids who want to go from land to sea without changing vehicles? Luckily for you, Aquada and Humdinga (that name still kills us) manufacturer Gibbs Technologies has just revealed a prototype product that's sure to be hit with the younger crowd at your summer house: the Quadski dual-purpose ATV / jet ski. Equally at home in sand or surf, the Quadski can hit a claimed 50 miles-per-hour traveling on either surface, thanks to a 140-horsepower engine and a propulsion system protected by no less than 60 patents. The switch from ATV to jet ski supposedly takes a mere five seconds, and a full tank of gas will give you either a 372-mile range on land or two hours to tool around in the water -- but don't go getting the kids too hyped up, because there's no word on when/if the Quadski will see mass production.
[Via Gizmag, thanks Madeleine]