Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Event Hunt - Startups and Tech Events Curated By Locals
Mobilizon - A free and federated tool to get our events off Facebook
Eventjoy - The Easiest Way To Organize An Event
DownToMeet - DownToMeet is a platform to organize, find, and attend group events.
Facebook Local - Discover places to go and events happening near you