Maze Rats
"The referee advice is gold. I know of few better sources for concisely explaining what to prioritize when running this sort of game." - Brendan S¸ Necropraxis¸ Wonder and Wickedness
"I often quibble with RPG magic systems either being too complex or too restrictive¸ but this hit a great balance between flexibility and ease-of-use¸ while adding a special dash of creativity and Lady Luck." - Ars Magisterii
"Maze Rats is a light¸ brutal roleplaying game of fantasy adventure which is supported by random inspiration aplenty¸ which lends itself to a lighter¸ slightly whimsical tone. It is quick to learn¸ quick to teach¸ and easy to play¸relying on player ingenuity and cleverness rather than a reliance upon the mechanics." - Reviews from R'lyeh
Maze Rats is an RPG and sandbox toolkit for old-school-style adventuring. It contains a single¸ compact page of rules¸ a one-page character creation guide¸ a hand-drawn character sheet¸ and eight pages of 36-item random tables¸ rollable with two six-sided dice. Each page contains 9-12 tables¸ covering spell generation¸ monster generation¸ NPCs¸ treasures¸ cities¸ wildernesses¸ and dungeons. If you run (or have always wanted to run) open sandbox adventures¸ Maze Rats offers everything you need in a compact¸ easily-referenced format. Also included is two pages of advice for preparing and running open-world games in the OSR style.
The game system itself is 2d6 based. Character are extremely quick to generate¸ making it great for convention games¸ one-shots¸ or introducing new players. The game is highly lethal¸ and assumes a style of play where caution is essential to long-term survival. It is technically classless¸ but the leveling options allow players to specialize in fighting¸ thievery or wizardry or some mixture of the three. Magic is simple and chaotic¸ with new randomly-generated spells filling the magic-user's head each night. Everything about the game is designed to be as clean¸ fast¸ and intuitive as possible¸ while driving players towards creative solutions rather than brute force (though brute force is always an option).
If you're looking for an adventure to run with Maze Rats¸ check out The Alchemist's Repose.