This is one of DC's great dive bars. The interior looks sort of like an evil Elks Club, all unironically old-school 'art,' cheap paneling and dim lights barely illuminating the unapologetic slumminess. It's famed for its whopping, mix-it-yourself drinks, where you get a ketchup-type squirt bottle of booze, a can of soda and bucket of ice for $20. Cash only.
Dan's isn't marked, as the sign fell by the wayside a while ago, so keep an eye on the surrounding street addresses.