OpenQuest — a neat rules engine
I have always been fan of the old Basic Roleplaying rules engine (BRP) used in Runequest and Drakar och Demoner. Some time ago, someone told me that there is a streamlined OGL version of it, called OpenQuest, available here >>>
I have taken a look at it. Verdict: quite nice though of course old-school. Adaptable to most fantasy contexts.