GardenSLUG is the LEGO User Group centered on New Jersey and the surrounding metropolitan areas. GardenSLUG is two and a half years old, pretty informal, meets two to four times each year, and has roughly 20 members.
A few members of the online LEGO community from the Jersey/NYC/Philly areas attended BrickFest 2000 and were revved up about doing some local organization. Notes were posted to LUGNET newsgroups and the first meet was held on 22 July 2000 with the six founding members in Hillsborough, NJ.
GardenSLUG is an organization devoted to the sharing of LEGO-related ideas and good times. This includes getting together for local meetings, attending national LEGO conventions, and maintaining a somewhat cohesive online presence. Areas of interest to GardenSLUG members include LEGO: building techniques, collecting, gaming, conversation, display and demonstration, and working with kids. GardenSLUG is primarily, but not exclusively, an organization for adult fans of LEGO.
You can see a web page on GardenSLUG at http://www.lugnet.com/org/us/gardenslug/~45/.