If you have already mastered most of the Rubik’s Cube type puzzles out there, try your hand at this 8x8x8 8cm Speed Cube Puzzle.
Even those who have mastered other cubes may have a hard time with this one. Not only is it challenging, it’s also built for speed. It is spring structured for fast turning and the tension is adjustable. This one may take you a while unless you are an amazing super-genius.
You can buy the 8x8x8 Speed Cube from Amazon.com. It makes a great gift for anyone who loves puzzles.