Kubrick is a game based on Rubik's Cube and using OpenGL 3-D graphics libraries.
Kubrick handles cubes, "bricks" and "mats" from 2x2x1 up to 6x6x6. It has several built-in puzzles of graded difficulty, as well as demos of solving moves and pretty patterns. The game has unlimited undo, redo, save and reload capabilities.
I think this game is a must for every KDE (or Linux) user. A bit of time to get used to game controls. But once I reach that goal, the game re-creates a challenge that never dies through passing of years.