How long are you planning on being in DC? You will never see everything in one week. So for the first time visit, I would spend most of your time at the mall (Not the shopping kind either). The museums, the monuments, capitol building and the white house are all located near there. That will take you a few weeks to see everything.
You might also see about visiting your congressman and scoring Whitehouse tickets or a whatever they have to give constituents. You could search for military band concerts as well. They are always worthwhile. Sometimes there are concerts at the Iwo Jima Memorial. Mt. Vernon is always worth a visit. The Smithsonian Air and Space Annex out near Dulles is also very worthwhile.
regarding your trip to D.C.
great that you are giving thought. lived there 24 years. kinda disagree with other folks.
seen so many kids on trips dragged through mall.
depends on age. o.k. Lincoln Memorial AT NIGHT.
Neighborhoods. Capitol Hill. Eastern Market, not on Monday when it is closed. Adams Morgan. The sculpture garden and
outdoor skating. Indian Art. Library of Congress. Dunbarton Oaks in Georgetown.
Outdoor concerts near the Capital every Tuesday? night.