In the interest of contributing something at least semi-useful to other people I present Ye Olde Fumble Table.
This is something I put together back around 2001-2002 when I was running a 3rd Edition campaign every two weeks with 6-8 players and we thought the game just cried out for something to balance out the spectrum with the Critical Hit rule. I'm not as big on things like this now as it can slow down the game but we did have quite a bit of fun with it. If I end up running Pathfinder or a 3.5 game again at some point I might break it back out and expose a new generation to the joys of damaging oneself. I believe v1.2 was the final version after we discovered some results needed more clarity or to be simplified. If anyone is interested I can probably turn this into a PDF and put it up on Dropbox or Google Docs in a more printable format than this.
Looking over it again for the first time in a while, this really would not e difficult to translate into 4th Edition - all those wonderful conditions could fill out a fumble table quite nicely. Hmmmm.