Piecepack is the public-domain game system that is to board games what an ordinary deck of cards is to card games. It is a set of board game parts that can be used to design and play a wide variety of games. Anyone may design and publish a piecepack rule set. Any manufacturer or individual may produce piecepacks. Give it a try for free.

I liked chess and power-lines. They even have a regular design contest, so the games keep coming.