From HacDC Wiki
GrindDC's weekly meetings take place at HacDC every Thursday evening (rain or shine) and begin at 7:30p. Some attendees regularly show up earlier that 7:30p and folks typically trickle out when they need to, with the last folk leaving between 10:30-11:00p).
We mainly use Meetup.com to organize our meetings now. For the latest info, checkout: http://www.meetup.com/hac-dc/