Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
PartyWith - Connecting people who love to party - anytime, anywhere.
Event Hunt - Startups and Tech Events Curated By Locals
The Simple Postcard - Text a photo to mail it as a postcard
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
LinkedIn Events - A new way of connecting people from LinkedIn