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

Slack It - A bookmarklet to share links in Slack with one click

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

Slinky - Your slack links — organized!

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.

Top Daily Hunts in Slack - A simple, fast way to browse news within Slack