Another suggestion: contest to create a chess variant, which can be
conviniently played on usual chess board with usual chess pieces (may be
with more then one chess set, also it is allowed to use less pieces).
Piece moves should be also the same as in chess.
Example of such variants:
* different capture rule (e.g. Crazyhouse)
* different goal (e.g. Extinction chess)
* incomplete information (e.g. Kriegspiel, can be played with 3 boards +
arbiter)
* different move order (e.g. Marsellias chess)
* different starting position (e.g. Fisher random chess or Una chess)
* random elements (e.g. Dice chess)
* multiplayer variants (e.g Bughouse)
I think this is broad enough to appeal to many people.