For those who don't find the Knight's Tour challenging enough, try Troyis. In Troyis, you use a knight to move around the board, but you can only move on the white squares, and you must land on each of the white squares before time is up!

You can play solo for free, or play live with other players for an added charge. In both versions, you can see where you are in a full list of ranking players, as well.