After the Stonewall Uprising, he joined the newly formed Gay Activists Alliance. While Chair of the GAA's Municipal Government Committee, Rubin conceived of and planned of one of the group's most famous zaps, which took place at the New York City Marriage Bureau. When New York’s City Clerk Herman Katz threatened legal action against the Church of the Beloved Disciple for performing same-sex “holy union” ceremonies, about 35 GAA members showed up at Katz' office with donuts, coffee, and a wedding cake that was adorned with a gold Lambda, same-sex male and female couples, and the inscription “GAY POWER TO GAY LOVERS.” GAA members distributed leaflets throughout the building inviting city employees to the party that said, “The Honorable Herman Katz, City Clerk, invites you to an engagement reception for Messrs. John Basso and John G. Bond, Messrs. Steve Krotz and Vito Russo, at his office, Room 265, Municipal Building, Friday, June 4, 1971, at 10:00 a.m. All welcome. Dress optional. Sponsored by Gay Activists Alliance.” Rubin was quoted as saying the zap demonstrated “that everybody in New York had better know that they can’t push gay people around, because the community’s there and will stand up for its own.” GAA later showed videotapes of the zap at Firehouse dances, to help demonstrate to people the concept and power of zaps.