Fort Reno's summer concerts are a small D.C. institution, rooted in the city's punk and indie scenes rather than in polished downtown entertainment. The series began in 1968 and still has the feel of a neighborhood gathering that happens to carry a lot of local music history.
Check the current schedule before going, since weather and permitting can affect dates. If a show is on, it is one of the more relaxed ways to catch a piece of Washington culture away from the monuments.