Horizon - Horizon is a realtime, open-source backend for JavaScript apps.
WeShelter - Unlock a donation when you pass a homeless person in NYC
Nomad House - Houses around the world for nomads to live and work together
TAP London - Tackling the homeless problem together
ViaHero - Don't plan your trip yourself, let a Hero come to the rescue
Catchafire - Use your professional skills to help charities