Sudoku is hard, unless you're a math genius. Rubik's Cubes are hard, unless you're a math genius. Clearly, the math genius demographic was being underserved by the national brainfun hobby industry, until now. Enter: Sudokube, the Sudoku Rubik's Cube. It's all the infuriation of the world's most notorious puzzle-slash-paperweight, with the added complexity of a New York Times-level number theory exercise. Found via Forever Geek.