When original D&D was published, Mr. Barker tried to adapt the game to Tekumel, so other peoplecould go on adventures in this fantastic world. It was a mediocre success. So he developed his own set of rules, which is still in use today, played by people like Chirine ba Kal and Bob Meyer, to name just two. Chirine has told us again and again that Gary Gygax and Dave Arneson used these rules (or very similar ones) as well.
What you're about to see is NOT the cover of the rulebook. It IS the rulebook. These rules have been in use for at least 30 years.
The interest in the rpg community in super-simple, super-lite rules seems at an all-time high at the moment, and personally, I think that's good, very good indeed.
As you might have guessed, my favorite taste of rules-lite is Perfected, or to be more exact: opposed rolls. Using opposed rolls cut out two things that I don't like in rpgs: math. Checking stats to see if I rolled high or low enough.
Another rpg system using this method is the brilliant Sword&Backpack, written by Gabe Soria. Check it out here. The rules? Player character tries something, referee tells him what to roll with a d20, or rolls against them. Done.
Cecil Howe, he of Hex Kit fame, made a booklet version of Sword&Backpack, and it's a beauty to behold. The booklet version adds a rule: Whenever a character is trying something that is appropriate for their background or profession, add 5 to the d20 roll.
Cecil also published a zine for Sword&Backpack (unfortunately only one), called Peril, and yes, it's good! In Peril, Cecil also introduced a new concept he calls "Difficulty". To quote: "This is the number of combat rounds a monster can lose before it is defeated, think of the D as standing for difficulty. The number can be any number, not just one. Really tough monsters will have a high number, and really flimsy monsters will have a low number. "
Bob Alberti is the treasurer of the Tekumel Foundation. He played in Prof. Barker's game for over 20 years. His ruleset is, as you might have suspected, similarly simple. To quote: "You have dice to resolve any questions (01-10 good, 90-00 bad, use common sense). (…) All the other crap - character stats, encumbrances, combat rules, etc., are the tools of the rules-lawyer, and not worth the attention of dignified persons."
Today, Claytonian published his one-page rpg "The Party". And lo and behold, it uses opposed rolls to solve everything. Check it out here.