Several people have suggested that the spy museum is a but pricey. Does anyone have any other ideas for somewhere to have a long hair meet in DC?
The portrait museum and Smithsonian are both free.
You could just pick an easily recognizable landmark (like the Washington Monument, for example), use that as a connection point, and then figure out where to go once you have everyone together.
Also, there's a food court in the lower level of the Reagan International Trade Center, which is just north of the mall and right by the Federal Triangle Metro stop.
I think what Garth means is the National Portrait Gallery and the American Art Museum. These are connected, so you can go from one to the other.
Another possibility that's been suggested is the US Botanic Garden. This is also on the Mall, whereas the International Spy Museum is in the downtown area.
When we have a place and time fixed I will contact everyone who's expressed an interest. AFAIK the date will be September 6th, but that's the only thing fixed so far.