All of the advice in this thread is very good. QBall is a great room, but not super convenient from Navy Yard. Rocket Bar in Chinatown is just okay. Very disrespected GC tables. They are 9 footers, but usually dirty, nappy cloth. I play there a lot anyway. Continental in Rosslyn has a mix of 7, 8, and 9 footers. They have APA Tuesdays and Wednesdays, and sometimes a tournament on the weekend. Bedrock up in AdMo has really well looked after GCs with quick cloth. You can usually find a game up there. I've not been to Atomic in years, but a friend of mine plays APA there, 9 footers.
Out in the burbs, there's all sorts, but if you're in Navy Yard you probably aren't looking for a road trip to find a game. Welcome to the city. Check out Shilling Canning and Bammy's in your neighborhood. I've always enjoyed them both. I'm at the Wharf, so hit me up if you need a game.