If you're looking for an easy introduction to hardware hacking, this article might be the perfect entree. Create your own piece of desktop Frankenkitsch by breeding one optical laser mouse with one NES controller. It's functional, and it's lovely.
The author picked his NES controller up at the Salvation Army, but eBay is listing several for under $5.00 right now.
It may not be as ergonomic, but answer us this: did you ever get RSI as a child? No. Of course not. It was only once companies started foisting so-called ergonomic products on us that RSI became prevalent. (Spot the logical fallacy!) Return your wrists and hands to their youthful dexterity and nimbleness by using a Nintendo controller at least three times per day.
[Thanks, Jordan Chong]