There are a lot of things that take 20min in DC: security lines at Reagan, waiting on the last train at 2a, trying to find a cab in Greenbelt after you fell asleep and missed your stop on said last train. Now add "get to an amazing winery" to that list, with The Winery at Bull Run.
Located just 20mins outside the city in Centreville, VA, the just-opening winery is now the closest one to DC, and is ready to serve you its nine varietals on a "working farm vineyard in an authentic 1860s setting", which translates into sipping locales like:
The Vineyard: It sits on 2+ acres, and seamlessly blends with the Manassas Battlefield next door, though the only charging you'll be doing is to your credit card, for more of their delicious wine!!
The Main Barn Tasting Room: With its stone bar and cafe tables sitting below a 20ft mural of the property in the 19th century, the barn also houses a museum filled with Civil War relics found on the grounds.
Stone Mansion House Ruins: They've built a beautiful, open-air stone patio atop the ruins of the original estate house, complete with country seating and a fireplace, which may or may not have been the reason you're sitting on ruins.
And if you just can't decide where to enjoy your glass, come back a few times and join their $50 General's Club, which'll get you access to complimentary tasting events and the soon-to-be-built, members-only Battlefield view deck -- perfect for watching reenactments, assuming your attention span is more than 20min.