Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Tripadvisor - The Tripadvisor mobile app is available for the Android and iOS platforms. It can be used to create reviews of hotels, restaurants, and to chat with other travelers on Tripadvisor forums.
Zoho Backstage - Plan, run, and analyze your event— all from one place
NetBuddy - Netbuddy is a virtual network operator for a mobile device.
Meetup for iOS and Android - Discover groups that are all about the things you love
Wikivoyage - the free worldwide travel guide that anyone can edit.