Cruise ship water parks are a top-deck jumble of cascading tubes in Crayola colors, cartoon characters playfully spraying into kiddie pools, and delighted screams that splash out of slides and from behind water cannons. These water playgrounds are an especially attractive diversion on the warm-weather itineraries offered year-round by most cruise lines. Cruise ship water parks are being quickly one-upped as cruise lines get creative with their brand-new ships. Innovative slides that thrill riders with drop-out floors, two-person floats and spiraling funnels now include dazzling light effects, and expansive top-deck areas have added even more square footage and water features as cruise lines roll out their largest water parks to date. In today's world of water parks at sea, five cruise lines stand out because of their impressive aquatic chops. Here are our favorites.