Recently I stumbled upon a new rules-light roleplaying game called “Dungeonslayers”. Dungeonslayers consists of 12 pages of rules and is meant as a fun and easy to play fantasy RPG. There is no setting provided with the rules and it’s obviously meant to run dungeon adventures but I am sure you could easily run any kind of adventure. The game is free and was released unter Creative Commons 2.0.
There is currently only a german version of the rules, but since it’s released under CC it should be no big problem to translate it to English.
The official site has the latest rules and several character and equipment sheets available for download.