I can't believe no one has reviewed this place yet -- besides Toys R Us, this was one of my favorite places to go to when I was a kid growing up in Madison. They have several sections including rocks and gems (including a whole wall of glow in the dark rocks!) and dinosaurs/fossils. For better or worse, I am certain that I kindled my everlasting love for shiny rocks right here at this museum.
Not sure if it's still there, but there's also a small gift shop if you'd like to take a little piece of the museum home with you, or start a full blown rock collection, like I did.
All in all, this museum is definitely worth checking out, whether you have kids or are an adult who likes cool, shiny rocks and/or dinosaurs. My Dad and I still try to stop by anytime we have a family vacation back to the midwest, at least to check out the rocks. Sometimes I still buy one from the gift shop to take home with me.