Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
MinglePic - Share your event photos with everyone at the party
Event Hunt - Startups and Tech Events Curated By Locals
Texty - Text photos and see them online
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Open Cult - A place for people with common interests to meet IRL.