My entry for Christmas Experiments 2014
Made using the awesome three.js library from @mrdoob and friends
For the sun I'm using @bkcore's technique for volumetric light as described here http://bkcore.com/blog/3d/webgl-three-js-volumetric-light-godrays.html
The terrain is generated using noise shader from @ashima https://github.com/ashima/webgl-noise