The Potomac Appalachian Trail Club - Mountaineering Section (AKA Potomac Mountaineering Club, AKA PATC-MS, AKA PMC) is doing its annual New Climber Day. The event is free and open to non-members (though you will probably be asked to join). They will even provide shoes, harnesses, and helmets. The main purpose of the event is to expose people to "real" outdoor rock climbing.
More details and the "official" RSVP form are at http://www.signupgenius.com/go/4090E4FA8A622AB9-newclimber