http://www.jamminjoesbbq.com/ I stumbled upon this on a drive towards Warrenton along US-29. It's a little mobile stand, with smoke visibly rising from the steel pit. No indoor seating, you just walk up to the window and order. I found a mini review in the Post from 2004: http://www.washingtonpost.com/wp-srv/metro...e/virginia.html
All I tried was the pulled pork sandwhich, no sides. I thought it was the best BBQ I've had anywhere in the DC area, and as good or better than what I was able to sample on a recent trip to South Carolina (where I had some very good BBQ).