re: Must do's in D.C., Including restaurants

Of course, museums around the Mall....but if you're into aircraft, the National Air & Space Museum has a branch at Dulles Airport. You can see the space shuttle Discovery, the Concorde, spy planes, etc (a bunch of cool stuff too big to fit inside the Air & Space museum on the Mall). Well worth the metro to bus transfer, or an early side trip if you're flying in & out of Dulles.