If you enjoy playing chess, you will want to pick up the $4.99 Chess App by Swedish app developer Memention AB. The app is a standard, play-against- the-computer chess game with 5 levels of play. I was able to beat the computer at levels 1 and 2, but lost at level 3 (I am an intermediate player, with a rating of about 1500). Generally speaking the computer makes its moves almost instantaneously, and rarely makes blatant mistakes. You can always undo any and all of your moves without penalty.
One of the nice touches of the game is that it requires you to name each game, and then saves a record of that game. You can go back to old games, and see the list of all moves, and even undo your old moves and pick up the game from a previous position.
The game is well worth the $5 price tag. I wish there were a 2 player mode, where I could challenge a friend (or possibly a stranger like in rooms such as Yahoo chess). Also, there should be a way to replay past games, and not just undo them. Still, at this early stage, I recommend the app.