TechEvents.co - Tech and startup events aggregator
Eventjoy - The Easiest Way To Organize An Event
Facebook Local - Discover places to go and events happening near you
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Hop - Spike makes working easier and more efficient. Saving you and your team time, sanity, and a lot of headaches.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.