Full Command is a 7 page core ruleset for simulating battles all the way from a skirmish level with a handful of individual models through to full scale war with units totalling hundreds of miniatures.
Full Command has been designed to be setting and scale agnostic. It can be used to play 28mm skirmishes in an ancient setting to 15mm ranked warfare in a medieval fantasy setting to a 32mm heroic squad based battles in a far sci-fi setting.
Full Command is being released under Creative Commons (Attribution-ShareAlike) to allow maximum flexibility and freedom to gamers everywhere. Always wanted to play that game where Zombie Alien Pirates are battling the Savage Ape-Men on Mars? Grab the core rules, whip up a setting module with a couple of factions and you're away.
N.B. As of January, 2016, Full Command has been merged with Realm - Fantasy Warfare to form Full Command Fantasy Warfare as a complete game and is no longer strictly modular in nature.