This is not a large museum by any means, but has several activities for kids and does a fantastic job explaining the flour production process and the history of flour production in Minnesota. There's also an elevator tour up to the 9th and 10th floors where you can get a good view of the surrounding landscape and see the remaining structure of this old flour production site.
If you have a free morning or afternoon, I encourage you to check out this museum. It's very cool and very informative. It took me about 90 minutes to complete both the self and guided tours.