Here's a counterintuitive thought: if you want your child to lose weight, turn on the video games. Several new studies show that "exergaming" systems like Dance Dance Revolution (DDR) and the EyeToy, which require users to dance, kick and dodge, may help them shed unwanted pounds. In January the Mayo Clinic, in Rochester, Minn., found that obese children burn six times as many calories playing DDR as they do with a traditional video game. No surprise perhaps, except that they also like to do it. Even more encouraging: college students burn twice as many calories using an EyeToy as they do walking on a treadmill. But how do exergames compare with an hour of basketball? The jury is still out.