Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
GoPad for Schools - School Management
Zoho Backstage - Plan, run, and analyze your event— all from one place
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Meetup for iOS and Android - Discover groups that are all about the things you love
Tuio.org - Tuio is a billing and payment application that allow daycare centers and pre-schools to centralize and manage all parent billing and payment in one place.