I am the course designer and one of the promoters for a popular Cyclocross race at the Old Soldier's Home (AFRH).
It's a fun sport and also great for spectating- Free Admission. Free Parking, or ride your bike there.
Races are all day Saturday, with the Elite women and men in the afternoon. 5pm at fun Relay race.
Registration and info :
https://www.bikereg.com/dccx
Entrance is on Randolph St and Rock Creek Church Rd.