We have two great new showcases up on the Cesium demos page.
CITISENS is a mobile application that allows ordinary citizens to report wildfires by pointing a smartphone camera at a wildfire hotspot: http://cesiumjs.org/demos/Citisens.html
The Paralog Performance Competition site is a place to track wingsuit flights and judge wingsuit competitions: http://cesiumjs.org/demos/ParalogPerformance.html