Reversi

How to play: you play black and go first on an 8×8 board. Place a disc so that it traps one or more of your opponent's discs in a straight line — across, down or diagonally — between the disc you just laid and another of yours: every disc caught that way flips to your colour. Every move must flip at least one disc, and a player with no such move loses the turn. When neither side can move the board is counted, and the colour with more discs wins.