A roommate is moving out and we now have a basement room available for rent in our house in Clarendon/VA Square. I'm a DC Tri member (newbie triathlete). The other roommates are a runner and a pilates enthusiast. It's a pretty active house overall, in between jobs and social activities.
See the add on Craigslist: http://washingtondc.craigslist.org/nva/roo/3816983763.html