Way back in 1996, I created a patch to remove the GIL from Python's interpreter (version 1.4!). Dave Beazley just picked up the patch and tore it apart, and writing a fantastic blog post. It is quite nostalgic for me, from back in the day when I was working at Microsoft on their electronic commerce efforts.
[ I commented on Dave's post; it provides some context that you may also be interested in reading ]