Welcome to a slew of pages devoted to Mike's favorite gaming system: MYTHUS!
Yeah, if you're not a big Mythus fan, some of this won't interest you (much), but you should still check out the Mythus Castings, since they can probably be used under many different systems with a little work. You can also check out the GURPS home page, which is a site devoted to my second-most favorite game.
Mythus is a percentile, skill-based system that is, in its most basic form, extremely simple and straightforward, but in its permutations, the true depth of the system comes out.
I do keep a list of what's been changed, which is usually pretty accurate, to help people track changes.