Mobilizon - A free and federated tool to get our events off Facebook

Calendify - Calendify is an event community where you can share, publish, and subscribe to event calendars. It helps you to stay informed about what you are interested in and what is yet to come.

Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

Upcoming.org - A simple way to share and discover interesting events

DownToMeet - DownToMeet is a platform to organize, find, and attend group events.

Morse - Create, shout out, and discover nearby events in real time