A 3D engine written in JavaScript. All the 3D stuff is pure HTML5, mea3D uses no Flash, no Silverlight, no DirectX or no OpenGL. The engine supports transformations, lighting, loading of custom 3D models in JSON format and has some other cool features.

It even has a raytracer which can render reflections and shadows!

Check out the (candidate) Chrome Experiment using mea3d at: http://mustafaacer.com/chrome_experiment