A number of demos have not been updated to the latest spec. They are listed here, in hopes that they will be updated in the future. These raise various errors or just simply don't work when executing.
WebGL port of Auld's amazing 1K demo, Chocolux. Chocolux is a real-time recursive GPU raytracer using four spheres. There are only 2 triangles on screen; all of the ray tracing happens in the fragment shader. Chocolux's raytracer does a few things for distortion (reuse of a loop variable in an inner loop) to achieve the stylized effect and the small footprint.
Interactive viewer for virtual reality panoramas.
Emanuele Ruffaldi has also written a number of other other WebGL demos
Aaron Babcock's version of a classic Flash game
Realtime cartographic re-projection of raster and vector geo data using vertex shaders. Introductory blog post