Castaway Bay Indoor Water Park at Cedar Point in Sandusky, Ohio

There's snow on the ground, but there are riders in the water slide tubes at Castaway Bay. Indoor water parks offer year-round, weather-proof fun. The enclosed water slide tubes, which begin and end inside the climate-controlled, 84-degree park, remain warm even when it's frigid outside. Indoor water parks like Castaway Bay send some of their water slides outside the building to save valuable interior space.