Mobilizon is the Fediverse's free open source federated alternative to Facebook Events. You can find out more and how to get started at:
It uses the same ActivityPub federation standard as Mastodon and the rest of the Fediverse (though it does not yet federate with Masto).
Discover & explore Mastodon with no ads and no surveillance. Publish anything you want on Mastodon: links, pictures, text, audio & video.
All on a platform that is community-owned and ad-free.
Hosted by Stuxhost.