Challenger Role Playing Game Core Rules

From the Introduction:

Welcome to the revised version of the Challenger RPG game! Despite appearances, this game is outrageously simple to learn and play. The bulk of the text is taken up by classes and races of which there are very many indeed. You should not feel you have to read through every single one to learn to play this game, instead, just read the chapter headings in each section and you will know all the rules you need to play. Better yet, grab a few friends and start play right away with the quick-play version and sample adventure (at the end of this book). You can always 'add-in' the advanced rules and character additions later if you want.