Berkeley Macintosh Users Group

The Berkeley Macintosh Users Group, or more commonly "BMUG", was the largest Macintosh User Group. It was founded in September 1984 by a group of UC Berkeley students including Reese Jones and Raines Cohen as a focal-point for the nascent Apple Macintosh user community.

Source: Wikipedia — Berkeley Macintosh Users Group (CC BY-SA 4.0)