Not sure if one is in Richardson, but we go to Lifetime Fitness in Plano on Preston and Legacy. It's a very family-oriented gym with tons and tons of classes for children. They offer karate for kids I know b/c I've seen them in the raquetball area. I also know that they offer periodic camps for children with lots of fun activities that get kids moving. They also offer swimming and tennis lessons. Not sure which kids' classes are included in your membership dues, though. Lifetime also has indoor and outdoor pools with waterslides. My kids are still too young to be taking those classes, but they absolutely love the child care area. It has a mini basketball court, an indoor play center, an outdoor playground, and a computer/coloring area. Every mom I've ever talked to has said her children (all ages) love coming to Lifetime.
For us mommies, Lifetime has a huge variety of classes, including kickboxing, dance aerobics, yoga, pilates, water aerobics, step aerobics, etc. They also offer classes (like Team Weight Loss and Bootcamp) and personal training for an extra cost.
We go pretty much every day, and we love it!
The phone number for the Plano location is ###-###-####, but your membership is good at any Lifetime Fitness location.