Seminar Space
I did a search on Wizards.com for stores with Organized Play sites and found a few places:
I don't know about referring to the event as a pagan event,

but here's one in Laurel, MD.
The Crystal Fox
"Interested in running a seminar or having The Crystal Fox host an event?
The Crystal Fox has an excellent seminar space and has hosted a wide variety of workshops, book signings and events of interest to the local pagan community at the store. For more information about the space or to discuss an event contact Sterling on 301 317-1980."
No offense, but I checked through the locations of people that posted, and there are more people that are either north or north east of DC than south of DC. So, the Woodbridge area wouldn't seem to make sense. I think Laurel might be a good compromise or maybe something in the Bowie area?
Also, I could help with shuttling people between metro stops and the final location.
Anyone have a spouse/teenager/friend that would be willing to set up babysitting? I've got 4 kids and Torin and I would both be interested in attending, but would have to figure out what to do with the munchkins. Although our oldest (age 11) would love to play if permitted.
Sephera