White House/elipse and the mall. There are proper field turf fields at the north end of Crystal City, but more organized matches than pick up matches. If I still lived in Crystal City, I'd definately be able to help organize some games. I still could give it a shot...
I've seen games at Gravelly Point, but its very, very hit or miss.
Capital Coed Soccer League, MDCVSA, and a few others leagues would be worth a look.
[This message has been edited by TXAggie2011 (edited 7/3/2012 11:56p).]