Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

Facebook Local - Discover places to go and events happening near you

DownToMeet - DownToMeet is a platform to organize, find, and attend group events.

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

CooMeet - CooMeet is one of the best and leading next generation of video dating web-based application specially designed for those users who want to talk online to people they have never met.

TechEvents.co - Tech and startup events aggregator