Any great exercise ideas for an overweight child?

Make it fun. The key to helping an overweight child exercise is to make it fun: sports! It can be as simple as a family softball game. Soccer is low impact and burns up a lot of calories. There are under (x age) teams everywhere. Tennis with supervision is so much fun. Lead by example. Take your kid to the tennis court. Get lessons for both of you if you don't know how. Swimming is great in the summer.