Domku
Domku, 821 Upshur Street NW, Washington, DC, 202-722-7475, closed Mondays (Metro Trip Planner - opens in new window) [Washingtonian | Wash Times | Hill Rag | WaPo | City Paper | Don Rockwell]
Mustard, pickled fish, meatballs, sandwiches, etc. I have yet to go, Thomas Head liked it.