I found these interesting projects on HTML5 Code.
Rome is an interative music video using WebGL and Three.js. This one is a must see, there is to much stuff going on to try to describe it.
This is a cool music visualizer written in WebGL.
Another WebGL project, this one demonstrates path tracing
This is a cool fractal using WebGL.
I missed the beta for this one but the Vimeo video is worth the watch.