It's the home of the United States Air Force Museum. A sort of Mecca for military aircraft geeks (such as Greg and myself).
I go at least once a year since it's only about 50 miles from where I live, and last summer Greg diverted south on a trip from DC to Oregon to visit the museum and we had a full day there.
Great fun and great company, but to "do" the museum fully it takes longer than a single day.
I take my 8 year old nephew every June, we hit the flight simulators, climb into the cockpit displays, bomber displays, hit the Omnimax and call it a day after 3-4 hrs.
Greg and I could of spent 8 hours just in WWII!