For all those out there with frozen fingers, I offer this solution: the humble heating pad, already available at any drug store or Wal Mart. Keep those fingers toasty!
This has finally gone on too long. I tried gloves, jackets, and wrist warmers, to no avail. Between the convection flowing across the backs of my hands and conduction to the cold desk, mouse, and keyboard surfaces, my fingers don't have a chance. Then I thought of a solution. Buy a cheap heating pad, and put it under my mouse and keyboard. Hurrah! Not a perfect fix, but so so so much better. I also turned my computer backwards, so that the fan exhaust blows towards me. That helps a little too.
Solving this problem did not result in a nifty design, and in fact does not seem very interesting at all. However, I've mentioned it to several other people who have commented on how cold their offices are, and they have all been surprised by this simple solution. That made it seem worthy of posting. I have since covered it with a cheap "backpack" from a trade show, and put a mouse pad on it.
Note: This was actually about 1 1/2 years ago, and I still really love it. The keyboard warms up too and keeps my left hand warm as well.