Running this meetup group has been fun, and I learned a whole lot. I'm moving out of state, so it's time to close the group (if you'd like to lead the group, send me a message through Meetup and you can take charge).
If you'd still like to get into friendly political debates, here's the best up-and-coming debate meetup in the DC Metro Area: http://www.meetup.com/americans-elect-DC/