Introducing fitness to kids

Do we have any parents here who encourage their kids to exercise with them? My daughter is only three and she is extremely active, so structured exercise for her at this age is not something I was considering. However, I started following the yoga workouts on www.yoga.com as my New Year's resolution and she loves trying to participate with me. She actually has some of the moves down correctly and I think it's a great bonding time for us.