Soup Kitchens in DC
Here are some places that can use your help year round.
Food & Friends http://www.foodandfriends.org/site/pp.asp?c=ggLMIYOGKrF&b=3747191
DC Central Kitchen http://www.dccentralkitchen.org/volunteer.php
So Others Might Eat (SOME) http://www.some.org/volunteer_main.html
Also, check with Greater DC Cares for other volunteer opportunities. http://www.greaterdccares.org/HomePag...
Church of the Brethren (quasi-schismatic Lutheran) at 4th and North Carolina SE runs a year-round operation, something like M T,TH and F or some such. and there's always Miriam's Table as well, they'd probably be able to steer you somewhere.
I seem to recall a thread on this in 2008, you might try a search.
oh right it was me (duh), and I didn't get very helpful responses, but here's the link anyway