Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Clever - syncing between education applications for K-12 schools
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Bylde - Bylde is a SaaS platform you can use to Start, Manage and Grow your groups and communities.
Claroline - Claroline is a collaborative eLearning and eWorking platform.