The Adventure Science Center in Nashville, Tennessee is great. If you haven't taken your kids there what are you waiting for. This place opened its doors in 1945 and has only gotten better with age. I would say kids ages 11 and under will love this place, to be honest I seen some kids 30 plus there having a great time as well.
The Adventure Science Center in Nashville also has a great planetarium with state of the art technology. When I took my kids to this place, there were two options at that time, The Stars of the Pharaohs and The Stars Over Nashville. We watched the Stars of the Pharaohs, we should have watched the Stars over Nashville. Don't get me wrong the Pharaohs exhibit was great, but we found out the Nashville exhibit had more to it. Watch a trailer here, http://www.sudekumplanetarium.com/schedule/PHARAOHS/.
Our kids loved the new Space Chase exhibit, they got hooked up to some cables and finally got to do some of that rock climbing their mom refuses to let them do.
You will easily spend more than two hours at the Adventure Science Museum, a great day for the family in Nashville.