A great museum, in a town that seems full of them.
I went to the Wisconsin Historical Society as well, but it's more a research library than a museum. Strangely, there doesn't seem to be any connection between the two places. This one is comparable to the museum section of the Ohio Historical Center; the WHS seems like the archives and library portion of that institution.
When I went there was a special exhibit about toys, which was amusing but definitely more for kids. There was also a small display of contemporary quilts. The main floors hold the usual history and prehistory exhibits, well done with informative text and interesting artifacts.
There's a gift shop with a very good selection of books, local and general, as well as T-shirts and knickknacks.