Announced first at the Esri 2014 User Conference a couple of weeks ago, and the topic of a recent Esri email campaign, it's worth getting the word out on. It's the Global Disaster Resilience App Challenge, a partnership of Esri and the United Nations, specifically the UNISDR - the part of the organization that focuses on disaster reduction.
There's a $10,000 reward for the best professional/scientfic app, and also best consumer/public-facing app. And remember you don't need to be a programming ninja - there are lots of app templates that can lift your idea.
For more details visit the Esri Global Disaster Resilience App Challenge website. The submission deadline is August 27, 5:00 p.m. (Pacific Daylight Time). Pass it on to your colleagues, your professional network, universities, etc.