...to make more robust tilt adjuster 'feet' for the Microsoft Natural Keyboard Pro. The stock ones are horribly flimsy, and I have a bad tendency to break them in moments when frustration gets the better of me.
I still wish Microsoft hadn't stopped making them, because I still think they're possibly the best "standard" ergonomic keyboard (as against complete redesigns like the Kinesis keyboard) ever made.
I've had some success in the past just screwing stacked rubber feet scavenged from other equipment to the bottom.