This isn't a review of the museum itself, but of the special exhibit they were hosting - Jim Henson's Fantastic World. I couldn't find somewhere to post a review of jus the exhibit.
The exhibit is traveling around the country for the next few years - and if you are a Henson Fan you should definitely try to see it. Here is a list of where it will be http://www.sites.si.edu/exhibitions/exhibits/henson/main.htm
The exhibit includes original posters, drawings and notebooks, video clips, as well as Muppets. Kids will enjoy seeing the Muppets, adults will enjoy the whole exhibit. At the end was a place for kids to put on a puppet show, make a storyboard and make a face for a Muppet.
It was very interesting to get an insight into the genius Henson was, and how if he didn't use an idea in one place, he would try to get it incorporated into something else.
Its at this museum until March 9th.