We went to the National Building Museum. It was really cool. I really liked the exhibit on building and the history of construction in DC. It is across the street from COE headquarters :-) No pics from inside the exhibits - just the building atrium. We had to stay within the rules :-)
Later last night we headed over to Ben's Chili Bowl. Apparently it is a DC establishment. Now I have partaken!
http://www.benschilibowl.com/