Here's a game that's really smart, challenging and will have you playing for hours.  Tap-a-Brick runs smooth, looks great and is amazingly designed.  The creator Balazs Vagvolgyi says: 

Use the arrows to rotate the block around all three axes. To move the block tap on the 5x5 grid over the 3D pit. The game will automatically find the shortest valid path from the current position to the new location. If it is not possible to move the block to the selected position, the block will move to the closest valid location.
When layers get completed, they disappear and score bonus points. If you manage to complete two or three layers with a single block, you will receive extra bonus.

You definitely need to play this game!!