There's been some nice stuff floating around in webGL, and one of my favorite is the Ashima noise code, a kind of perlin noise like (this may actually be perlin noise officially?) that seems very organic and can yield some great looks.
The "halts" in the render are simply because I'm inputting some different values during runtime instead of gradual interpolating to them. It's also a bit of a lo-rez render because I wanted to save some bandwidth.
The code is available, formatted as a Quartz Composer composition, @ http://kineme.net/composition/gtoledo3/AshimaNoiseExternalTextureWarp
After using it for texturing things, for making generative patterns, etc., I had the idea of using it as a texture warp, and the results were more fun than I expected. It knocked around for a day, and then I added some normals with some use of the backbuffer/z.channel. I wound up adding some different modes to change the way the noise got calculated to displace the texture, some modes without lighting and with, some color control, and gamma (with a really useful utility gamma function I picked up from psonice).
With some careful use and texture input I've been able to make things that look like everything from fast generative landscape with islands and water, to eerie melting flesh, to very psychedelic organic fractal-ly looks by processing fractal equations with this.