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.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Iventlist - Create an app for your event in minutes 🎟️
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Meetup for iOS and Android - Discover groups that are all about the things you love