Platemail is a free RPG based on the seminal Chainmail wargames rules. The Book of Magic is here.
RPG Fantasy
Dungeon Tiles To Print and Play
Quests of Legend has a nice collection of dungeon tiles for you to print out and use for your role playing or miniatures games (or both!) in a dungeon crawl.
Machinations Steampunk RPG
Machinations is a simple steampunk RPG. From the author’s description:
Welcome to the Eternal City, the home of the Machinations RPG. Take on the role of an Adventurer, an Alchemist, an Artificer or even a deathless Automaton. Band together with others to form a Free Company and then hire yourselves out to perform acts of sabotage, espionage, assassination, extortion, blackmail or plain old robbery. All in a world a short step from our own, where reason has been lost, empires exist to be built and strange technology dominates all walks of life. It is a world of sinister intrigue, awful power, terrible events and dark portents. There is also beer, song and glory
Random Dungeon Generator
Here’s a nice random dungeon map generator. They have a very old school look.
Swords and Wizardry RPG
Swords and Wizardry is yet another free, old school fantasy RPG