We have two great new showcases up on the Cesium website:
http://cesiumjs.org/demos/OrbitLogic.html
The Orbit Logic Collection Planning Software Visualization generates collection plans for imaging satellites using spacecraft modeling and advanced scheduling algorithms.
http://cesiumjs.org/demos/IMERG.html
Real-Time Global Precipitation from IMERG shows how much precipitation recently fell, worldwide, according to a constellation of satellites.