We've got games like 2048 to thank for Amsthrees, a sliding tile game where the objective is to make the highest multiple of three that you can.
Each time you move the tiles in the grid, those labelled 1 and 2 merge together, as do any pairs that are in alignment. A new tile of 1, 2 or 3 is also introduced to the grid as well, so if the move does not result in at least two tiles being merged, it starts to fill up. A good strategy is to try and keep your highest number in the top left hand corner and build its pair in the square below. Employing this technique I seemed to get higher numbers.
Amsthrees has a nice soundtrack and the tiles scroll smoothly. Obviously it doesn't have much in the way of graphics but it does have bucket loads of addiction. When you lose, it's very tempting to immediately try again. As with 2048, you could easily lose swathes of your life playing this one!