How can we interest our kids in exercise? According to this article ("8 Fun Ways to Get Your Kids to Exercise"), the answer is "by giving them activities that are fun, stimulating and unexpectedly burn lots of calories."
1. Play interactive video games (the kind that "get players up and moving")
2. Create a rewards system to give them an incentive to acknowledge good behavior
3. Make your backyard a playground
4. Take up family sports -- play together!
5. Sign them up for sports -- try different ones early in their lives and let them find out which ones they are good at and like the most
6. Take the family to sporting events -- let kids see for themselves how being physically fit can pay off
7. Walk or bike to your destination (or park halfway there and walk the rest of the way)
8. Get in the water -- especially relevant in the summer, when most everyone wants to splash around in a cooling environment.