If you decide to go to Chinatown, go to Tony Chen’s Mongolian Barbecue on H Street. It’s the best chinese in the city.
For the best little burgers, The Ugly Mug’s are on top. 8th Street SE (Eastern Market Metro)
Old Glory BBQ on M Street in Georgetown. Nice array of BBQ styles. Great food, prices and location.
Clyde’s of Georgetown (M Street) or Chadwicks of Georgetown (K Street) for lunch. Clyde’s is commonly known as the best burger in DC. Chadwick’s is nearly as good and you might recognize the inside from the many films and tv shows that have shot scenes inside.
If you happen to go to the National Cathedral, be sure to get Pizza at 2 Amy’s, located just a few blocks from the Cathedral on Macomb St. or grab tex-mex at Cactus Cantina. The flavors at the Cantina are unique, some people love it (I do), some don’t, but the margaritas are the best in town. Both are family friendly, especially Cactus Cantina which gives take home souvineer cups for the kids.
Teatro Goldoni(1909 K St NW): at night, this is an expensive place, but for lunch, get the "Bar Lunch" seated at the long marble bar and for $12-$13 you get an entree and glass of wine. You might bump into a celeb here.
3rd & Eats (500 C St., NW, Judicial Square metro) $5 gets you a made to order carved roast beef or carved turkey sandwich. It’s a non-profit restaurant that uses its profits to help feed the poor and homeless in DC.
Full Kee (509 H St NW – Chinatown) hands down, has the best Wonton Soup in the city.