Tematris
To those who think tetris is an easy game, enter the world of a 3 dimensional tetris. Tread lightly as this game is not for everyone. If you wish to see the truth enter the tematris. The problem is choice, as always.
Challenges you with many shapes and colors and don't forget the layers below as it is hard to see from above. Many buttons are designed to explain the direction you want to turn the object. Fill the layers and feel the satisfaction it brings.