Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Circa - Find a time that works for everyone, in every time zone
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
CO Everywhere - Hyper-local news for every neighborhood in the world
Bigtent - BigTent is a web-based organization and communication portal for groups.
SpotlightNews - Now your newsfeed is authentic, local and 100% yours