Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Foursquare City Guide - Foursquare City Guide is a Free to use mobile application that will lead you to the perfect spot anytime anywhere around the world.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Sygic Maps - The world's first online maps designed for travelers
Bylde - Bylde is a SaaS platform you can use to Start, Manage and Grow your groups and communities.
Flamyngo - Create a city guide with help of your friends.