Many Smithsonian museums surround the National Mall. They are all excellent and free. You can check out the monuments and memorials while you're there. Some of our favorites include the American History Museum, the Hirshhorn Museum and Sculpture Garden, and the National Gallery of Art.
The Wharf is a new development in DC with lots of great restaurants and activities. Kids can play life-size board games and roast marshmallows at Camp Wharf. One of our favorite restaurants is Mi Vida, but you can't go wrong with any spot on the Wharf.
Georgetown is one of our favorite neighborhoods for dining, shopping, and walking around. Some of our favorite places are Martin's Tavern (where we ate the night we got engaged), South Block, YELLOW, and Thomas Sweet.