Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Greater - Pop-up support group in your pocket
Facebook Local - Discover places to go and events happening near you
Huddle - Huddle | The Enterprise Content Collaboration Platform
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Moodprint - Effortlessly track and analyze your moods over time