Ray tracing on GPU - demos?

Does anyone know of some (downloadable) demos showing ray tracing on GPUs?

I’ve found some papers about it, but seeing is believing and I haven’t found any demo yet.

I think on www.cgshaders.com there is a demo of a raytracing-shader. However it doesn´t run on my Gf4 :frowning:


That’s because they use a fragment program. The gf4 doesn’t have a powerfull enough fragment processor to do such a thing.