The FOSS4G (Free and Open Source Software for Geospatial) conferences are a favorite among the Cesium team. The Call for Participation has opened for the next conference, FOSS4G NA in Raleigh, NC in May 2016. I am happy to be part of the organizing committee.
The Cesium team will be there, and we encourage everyone to join us and submit proposals for talks or workshops on what you are building with Cesium or any other open-source geospatial tools.
For more info, see: http://cesiumjs.org/2015/10/29/Contribute-to-FOSS4G-NA-2016/