Eventjoy - The Easiest Way To Organize An Event
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.
B12 Bookings - Bookings scheduling software that integrates with your site
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Klook - Discover & book amazing experiences at exclusive prices
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.