There was a water play area for the kids to get absolutely soaking wet. It would be a good idea to bring at least one set of dry clothes (including underwear, socks and shoes) for everybody.
Check out the massive Rainbow-type play set in the back (I hope that it's still there). The thing was three to four levels tall and big enough to get lost in, literally. I wanted to play on it.
There was display that showed how the lego blocks are manufactured. Kinda cool if you're a engineer geek like me.
This park has lots of physical stuff for the kids to actually do. There are helicoptors that you control high you go by cranking or monorail-type cars that only moved if you pedaled. The place is pretty cool.