I've been here twice now, once about 2 years ago, and once about a few days ago. It really hasn't changed in all that time, ever activity is the same. I'd keep that in mind if you ever want to purchase an annual pass, I would recommend just doing the day thing to be honest.
It's a great place overall though for kids, I would say no older than 8. It is a very hands-on museum with lots of cool activities for the kids. They can paint, do crafts, climb a huge obstacle course, play with cars, ride tricycles, etc. It's really cool to just bring your kid and have them run wild for a good 2-3 hours.