We were just down in DC for the Cherry Blossom festival over the weekend.
For dinner we went to Woo Lae Oak in Vienna, VA for Korean BBQ and it was very good. A bit pricy, even more than NYC but Korean BBQ is always about that much. Free valet parking.
For Sunday brunch we went to the Roof Terrace Restaurant at the Kennedy Center. Very good quality food, reasonable price for a Sunday brunch. Lots of old dressed up people though. The views were also nice, but a little cold that weekend. You can go up to enjoy the view for free however.