If you're going into DC, check out Churchkey, they've got an excellent selection, with usually four or five cask conditioned ales which they serve at the proper temperature (yay!). In Silver Spring the best place to drink beer is the Quarry House, which has a very nice bottle selection, and is my favorite dive bar. I'd invite you over for some homebrew, but I'm going to be on the other side of the country. Safe travels!
Are you flying into Dulles? If you are try and stay out that way on your last day before you fly home. The Lost Rhino Brewery is out that way along with a few nice tap houses in Leesburg and Reston. If not and you have a rental car you could head out 270N to Gaithersburg and hit the Dog Fish Ale House its 20 min from Silver Spring longer of course during rush hour. http://lostrhino.com/ http://www.dogfishalehouse.com/locations/dfha-gaithersburg