OpenGL is one of those things I like to play with from time to time. So naturally I wanted to check out WebGL now that Chrome and Firefox support it.
Unfortunately it's noticeably slower than an equivalent program running natively. When profiling, the GL calls seemed to be the bottleneck. A bit less so on Windows than Linux, although that may have been due to better driver support on the former.
So like usual, optimizing comes down to reducing the number of GL calls you make per frame.
You can try out what I made at http://arcticpaint.com/planes/, play with the source or what ever. It's all under public domain (with the exception of the glmatrix library which has a BSD license).
I had also started toying with the idea of a turn-based game http://arcticpaint.com/islands/ (very, very far from completion)
If you want to check out more webgl stuff http://learningwebgl.com is a great resource. They also have some decent tutorials that are easy to follow along if you're new to OpenGL.