http://www.peace-action.org/gen/affne.html#MD You're also close by to the national peace action office. I also know there was a peace activist guy from Maryland who ran for senate with the Green Party (he was head of a national group) who lived in Takoma Park. I'm sure he's not popular at DU, but I'm pretty sure he was involved with a lot of local groups. One of them being Montgomery County Coalition for Alternatives to War, but I can't find a site. There's the Washington Region Religous Campaign Against Torture
http://www.wrrcat.org/There's also a group in Baltimore that engages in Civil Disobedience and is currently in a lawsuit against the NSA, Baltimore Pledge of Resistance.
That's all I can think off the top of my head, if I think of any others I'll notify.