Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Conode - A simple editor to organize meetings
Event Hunt - Startups and Tech Events Curated By Locals
Gathered - Make and share connections at events and meetups
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Let's Meetup - An easy way to share POIs and addresses in iMessage