Drupal is an open-source content management system (CMS) written in PHP/MySQL. The local Drupal Atlanta group has two meetings per month. A hands-on, workshop-like meeting takes place at Manuel's Tavern intown. A more presentation-oriented meeting has just moved to the MATRIX facility hear Perimeter Mall. Probably the best way to get with them is through their MeetUp Group. If you miss a meeting, please don't cry blue tears, though.