maje, a game of magic and attitude.
Duality, a game of dual natures.
Some alternate rules and additions to Risus, the Anything RPG by S. John Ross, including a version which uses one die and an alternate Risus Supers!
Four-Color Heroes, a superhero variant for Kathanaksaya.
A new superhero role-playing game, Larger Than Life. Rules-lite, uses polyhedral dice, check it out.
Here is Cinemania!, another rules-light RPG which simulates the world of movies. It is based on Mark Hughes' DUDE gaming system.
One-Page Fantasy Role-playing Game, a silly rules-lite fantasy RPG.
The transcript of an EXTREMELY interesting thread on RPG.NET that I started about designing superhero games.