re: Tips for DC and NYC

You really don't have time to do everything worthwhile unfortunately. There should be a stickied thread on this topic.

Of course, you'll hit the Smithsonian and everything on the Mall, and that's a fine thing to do. Here are other options if you had a couple of weeks more, in no particular order. But they're all worth a visit.

National Cathedral, Spy Museum, Newseum, Roosevelt Memorial, Udvar-Hazy (near Dulles), Marine Corps Museum (in Quantico), Baltimore Aquarium (in Baltimore, duh, but it's worth the trip), National Zoo. Plus everything else I didn't think of just now.