*Rallying event and community organizers in Berlin to use* Mobilizon*, a federated, free software, and privacy-friendly alternative to Facebook Events.* Facebook Events dominates online event promotion ... even within the iconoclastic scene of Berlin. We seek to rally artists, clubs, and event organizers in Berlin (and elsewhere) to adopt a new, decentralized and federated, free software alternative to Facebook: *Mobilizon* [1]. In our talk we present the technical and political/social aspects of *Mobilizon* and call on participants to organize with us in order to: - register on *Mobilizon*, try out and post (or cross-post) events on the service, - provide assistance in hosting and maintaining a *Mobilizon* instance to introduce the service to the Berlin scene specifically, - contribute to the project by coding a custom UX with a Berlin identity, - draft a code of conduct for our community, and - host further instances to federate with the Fediverse. Disclaimer: The talk will be recorded as part of a documentary for ARTE dealing with online self-defense and free software. Many people feel held hostage by Facebook. One reason often mentioned is Facebook Events and the network effect within Facebook's walled garden. Event and community organizers in Berlin – many of whom are critical of Facebook – have been discussing reclaiming club culture from commercialization for several years now [2]. These cultural influencers have great power to change mentalities and behavior. Although alternatives to Facebook Events exist, none enables local communities to interconnect on a global scale on their own terms. Until now. *Mobilizon*, released in October 2020, is a decentralized and federated service using the ActivityPub protocol (a standard of the W3C). It allows people to find, create, and organize events. *Mobilizon* is developed by the NGO Framasoft [3] (‘Degooglify’ project, PeerTube) and is released under a free software license (GNU AGPLv3). The unique federated architecture prevents monopolies, offers users a diversity of hosting terms of service, and allows communities to regain control over their privacy [4]. [1] https://joinmobilizon.org/en/ [2] https://media.ccc.de/v/fusion19-8553-reclaim_club_culture [3] https://framasoft.org/en/ [4] https://peer.tube/videos/watch/d9bd2ee9-b7a4-44e3-8d65-61badd15c6e6