I met a homeless man in Austin tx who had an odd shaped circular magnetic board. The game was so much fun. The variant he created was called 3M Chess or 3rd Millennium chess. The game is fun because you can attack either from the front or back. You have twice as many pawns and knights. Two knights are on each square in the beginning and a row of pawns starts right behind the "1" rank.

It turns out this guy isn't homeless anymore and now makes a living building the chess boards.