Port City in Alexandria is doing some great stuff, their porter is absolutely a must-try, and their witbier is quite good as well. 3 Stars, Bluejacket, Right Proper, DC Brau, and Atlas are all in DC-proper and worth checking out. If you can make it out to Sterling by Dulles Airport, Ocelot Brewing is doing some of the best stuff in the area. Phenomenal IPAs and pale ales, 20+ taps in their tasting room, and I have yet to be disappointed by a beer of theirs. Also obligatory plug for the brewery I work at, Sehkraft Brewing, we'll have a good variety of house beers by then, plus 35 taps of other local/international options, and we're just a couple blocks from Clarendon metro (orange line).