We've been a couple of times and the kids keep asking to go back! They especially love the big play area that has tunnels and slides that connect three levels of the museum!
Kent was also in heaven at the museum. They have a big section called 'mindbenders' where you can solve all sorts of puzzle, riddles, and play huge games. He would have LOVED this place as a kid.
My favorite place was the giant tree house. For whatever reason- it's always empty. You can see all sorts of great birds and the view is amazing.