A youngster's first dip can be anxiety-provoking for both parent and child, so the folks at Asphalt Green let the older generation into the pool, too. Easing the introduction is a special "warm-water pool," kept at a soothing 90 degrees, with a mechanical bottom that adjusts to offer the most comfortable depth, from a couple of inches to seven feet. While group lessons, which cost $18 per half-hour, are kept intimate with a swimmer-to-instructor ratio as low as five-to-one, private lessons are available for $40 per half-hour.