NVIDIA R267.24, R267.26 and R267.31 Beta Drivers
R267.26 is for GTX 560 Ti, R267.31 is for GTX 580 only and R267.24 is for all desktop GPUs. R267.26 is based on the R266_66 branch while R267.24 and R267.31 are based on the R266_45 branch (see the GPU Caps Viewer screenshot, the branch is displayed in the Driver zone) which has some bugs like a broken AO (ambient occlusion).
So if you want to test these beta drivers, here are the links:
Thanks NV for that mess…