I was visiting family in Rockford, IL and we wanted to take a day trip up to Wisconsin. My cousin searched the web for child-friendly activities to do in Wisconsin and found the Madison Children's Museum. I really loved the urban garden themed outside part. There is something here for every age. Check out the log cabin and ask the staff questions about it. They are informed and eager to tell you the history. All in all, if I find myself in Wisconsin again, I will visit.
A great thing about this place is that they honored my St. Louis Science Center membership card and my little one and I were able to enter free!
Also, take your child up to the roof. My daughter had the most fun up there holding baby chickens and petting the snake.