TechEvents.co - Tech and startup events aggregator
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
EventsApp - A simple concise app for creating and sharing events.
Facebook Local - Discover places to go and events happening near you
Sparq Events - 3D Social Networking
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.