The final assignment for Game Design I was to mod an existing board game into our own. Obviously, I started with Chess, and ended up with a game called "Knighted".
The basic theme, board, and victory condition were kept from Chess. The major changes were made to the pieces: their importance, and their movement. In Knighted, a player starts off with all soldier pieces (modified pawns), as well as two scout pieces (pawns that can jump, or weakened knights) and the captain (king). The soldier pieces, however, can evolve into stronger pieces (modified rooks and bishops) if it captures an enemy piece.
Check out the manual below for more detailed instructions.
The game came out pretty well, all in all. It probably could have benefitted from a couple more playstests, to really ensure that it was all balanced out, but since that time went into making the art look nice and the physical game look totally pro, I'm satisfied.