When I was looking for something to do around Madison, I came across this place. I thought it was a joke at first ("National Mustard Museum"? Are you kidding me?). It's no joke. It's all awesome. Where else can you taste (and purchase) thousands of mustards from around the world?
The first floor is the store, and the downstairs is the museum where you can watch a video on how mustard is harvested and see some of the historic mustards (you can't taste these -- I don't think you'd want to).
Make sure you buy a t-shirt that shows you as a graduate of "Poupon U"!
P.S. Mustard Rules! Ketchup Drools!