Here's another hair-puller for you, that is quite addictive. You must line up 5 balls of the same color either horizontally, vertically, or diagonally so that they will disappear, because when the board is filled with balls the game ends.The only balls you can move are the 3 in the upper left hand corner.

In the meantime several balls are floating around the board, and they can land anywhere they please-and usually in line with 4 of the same color so you are blocked. You can't move any of the balls on the playing field, so if you get blocked-you just have to try to move the block another way. This is nowhere near as easy as it sound.