The developers behind the Brigade path tracer (Jacco Bikker and Jeroen van Schijndel) have released two very impressive videos on Youtube and the jump in quality and performance is quite huge. The scene in the video runs smoothly on just one GTX 470 at 8spp and 640x360 render resolution (1280x720 display resolution) with very little noise:
This latest version of the Brigade path tracer contains at least two major improvements compared to previous versions: multiple importance sampling and a Blinn shader for glossy materials (e.g. the floor) which greatly enhances the realism of the scene (and seems to converge very fast). The kernel now runs on the GPU only.
Very impressive what they have achieved so far. With an extra GPU, the noise should almost vanish and become imperceptible after playing a while. And with Nvidia's Kepler and AMD's compute-focused GCN (HD7000) on the horizon, this path tracer is going to become very interesting (when the code will be ported to OpenCL in AMD's case). Something like real-time photorealistic chess rendered on the GPU is very close now. Jacco also mentions in the comments under the video that a new game is in the works with support for animated objects (including skeletal animation).
The mere thought of having truly real-time, photoreal global illumination in games is the most exciting thing that has happened in computer graphics over the past ten years. The last time I was this excited was with the introduction of real-time lighting and shadowing with normal mapping in Doom 3, first shown to the world on the MacWorld Expo 2001:
I can't wait to get my hands dirty and experiment with the new Brigade code.