Everything is bigger in Vegas, and this pool is more like a lake, sprawling across 11 acres. A river pool winds through the property before climaxing with a splash down a water slide. But the big attraction here is the beach, perhaps the most realistic imi- tation in the world. Not only is it broad and sandy, but the huge, lagoonlike pool it sits on generates waves that can be set high enough to host professional surfing competitions, though so far the hotel has been too busy to close the pool for one. Twenty-three rental cabanas ($150 per day) give families a home base at the pool complex, and the 10 deluxe bungalows ($200 per day) have their own private pool and several hot tubs; all come with misting systems to beat the desert sun. $159-$399; (877) 632-7000; www.mandalaybay.com

Doral Golf Resort & Spa, Miami, Florida

Doral is South Florida's most venerable resort, but the Blue Lagoon, added in 1999, is new. The complex includes an 85,000-gallon free-form zero-entry pool, with a waterfall cascading off the "mountain" next to it, and a larger serpentine pool winding through rock-lined valleys. The 125-foot-long water slide even comes with a radar gun, so kids can try for record speeds all day long. $259-$399; (800) 713-6725; www.doralresort.com

Great Wolf Lodge, Wisconsin Dells, Wisconsin

Family fun is the emphasis at this Midwestern resort, which boasts three separate water parks, two indoors and one out. The outdoor Thunder Bay has 800 feet of slides, an inner-tube slide, and a 6,000-square-foot activity pool with water basketball and other games. Inside the hotel, adjacent water parks offer 40,000 square feet of water play, no matter what the temperature is outside. Spirit Island, a Native American-theme pool, is filled with hand-carved totem poles and a three-story enclosed water slide. The Treehouse is just that: a fortlike, 12-level treehouse in a pool, equipped with spray guns and hoses for water battles, and topped with a 600-gallon bucket that constantly fills and overturns, dousing the entire treehouse. $139-$269; (800) 559-9653; www.greatwolflodge.com