On this latest episode of :That eReader does WHAT??" the Nook Color's 800MHz processor has now been overclocked to a full 1100MHz. Currently only for the rooted stock Barnes & Noble ROM, the new custom kernel adds some serious zip, and appears to be quite stable.
Our quadrant scores with the kernel max out in the mid-1200's, which are easily the highest we've seen on stock Eclair (overclocked Nookie Froyo yielded 1764).
The new kernel, from developer dalingrin, is easily flashed by downloading this zip file, placing it on your Nook's SD card, and installing in ClockworkMod Recovery.