PartyTalk - An efficient, fee-free event planning & ticketing tool
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Repartee - Social event planning rethought for the mobile era
TechEvents.co - Tech and startup events aggregator
XCalSync - Automatically copy events between your calendars.
Facebook Local - Discover places to go and events happening near you