I recently found a fitness program that I really like, Karate!
My daughter and I signed up a Parent/Child karate class through our local park district. I'm 39 and she is 7.
The classes are fun. They are not as repetitive as some other fitness activities, because you are always learning new moves. The classes are progressively harder and as you advance through the belt ranks they become exponentially harder.
My daughter and I were invited to belt test near the end of our first semester of classes. Usually most students do not test until there second or third session. They use a stripe system for the kids, so My daughter earned 4 out of the 6 stripes for her first belt, which is really good considering her age, and the short amount of time she had been in karate. For adults it is pass/fail and I earned my orange belt. We have both been moved up to the next level of classes. Last night was the first class for this semester, and it was definately a tougher class, but I enjoyed every minute of it.
I definately feel better since starting these classes, my weight is coming down, and my waist size is shrinking.