We had a recent foray to the Union Station museum down in Ogden. It was fun, and I was actually suprised to see that they had a lot of new exhibits since last time we went about a year ago.

If you are in the area, they do a reciprocal program with the Ogden Nature Center and Dinosaur Park. If you buy a membership to one, you get weekday admission to the others. They are pretty inexpensive memberships as well.