2-5 players. Each person is a different colour and you take turns to place a square of your colour (the big square tells you whose turn it is). For the first two goes you can go anywhere someone hasn't been, but after that you can only go to a place that is closer to one of your squares than anyone else's (indicated with a light version of your colour). If you have nowhere to go you will be eliminated and all the squares you previously owned become available again. You need to be the last person left. Every go there is a 50% chance a random square will be destroyed.
It uses Manhattan distance: the distance is determined by adding the horizontal distance and vertical distance so a diagonal is 2 away. It is much better with more people. It is better with turbo. I recommend a board size of 7 for a short game, 9 for a medium game or 11 for a long game.