Fidgitz™ - Thinkfun
This three dimensional mechanical puzzle begs to be picked up, and may be impossible to put down! Fidgitz twists and turns in a unique fluid motion that will mesmerize players for hours on end. Your goal is to twist and manipulate the puzzle until one side is all blue and the other side is all white. Invented by Bram Cohen of Bittorrent fame, and Oskar van Deventer. I love this puzzle. it is a delight to play with. You solve it and after one move it's gone and getting back to solved seems out of reach.