Mophidus is offering free PDF core rules for their Fallout Wasteland Warfare game, based on the Fallout video game series. They also are have a free Fallout: Wasteland Warfare Getting Acclimated pdf with some basic scenarios and a guide to help start play. Other free offerings are Fallout Wasteland Warfare Dice and Ruler Info and high res player cards.
Rules: Post Apocalypse
Autokill Auto Combat Game
Autokill is a set of free wargames rules for vehicular combat.