Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Coworker.com - Looking for the best coworking spaces? Read real reviews, get prices, see photos, view maps and more. Find your perfect coworking space in 100+ countries!
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Coworking.Coffee - The best coworking spaces all around the world
Bigtent - BigTent is a web-based organization and communication portal for groups.
Croissant - Unlock the hottest coworking spaces in your city