This is very cool: there is a new game called Sfera, it's using only spheres and is rendered with real-time path tracing on the GPU and CPU using OpenCL. The developer of the game, Dade (David Bucciarelli), is a LuxRender developer who is the first to make a working implementation of OpenCL-based unbiased path tracing on ATI cards. He created SmallptGPU, SmallLuxGPU and LuxRays.
Youtube video of the Sfera game: http://www.youtube.com/watch?v=Dh9uWYaiP3s
The demo features HDR image based lighting, bump mapping, multiple physically accurate materials, Bullet physics and multi-GPU support. I think it is absolutely awesome to see more developers using the power of the GPU (I'm glad that this time OpenCL and GPUs from ATI are used) to create amazing looking simple games with real-time photorealistic lighting. This game is a very nice proof-of-concept to show that real-time photorealism is very close. I hope this is the beginning of a paradigm shift for game graphics from rasterization to real-time ray tracing. The code is also open source and can be found at http://code.google.com/p/sfera/ (includes executables for Windows and Linux).
More info about the game Sfera can be found at http://www.luxrender.net/forum/viewtopic.php?f=17&t=7539
Btw, thanks Dade for mentioning Tokap and my blog on Sfera's project page ;-)