This jam is dedicated to creating content (new classes, new races, adventures, etc) for Six-Hack, the OSR homage to The World's First Fantasy RPG (1974), that has been released under a CC BY-SA license and is currently being Kickstarted. You can also download the working draft of the rules (a fully playable game) here. 

[Note: Art shown here, that will appear in the final game, by Carlos Castilho.]