With more than 43,252,003,274,489,856,000 (that's 43 quintillion) configurations and only one solution, the Rubik's Cube is still the best puzzle ever invented. Almost impossible to put down - there's even a Cubaholics Anonymous - the cube is an icon of design, and is the best-selling puzzle in the world. The current world record is an astonishing 7.08 seconds. There are also records for doing it one-handed, currently 17.90 seconds, and believe it or not doing it blindfolded (why?) at 2 minutes 41.54 seconds. It's quite likely that these records are well beyond the ability of normal people - because there's nothing normal about solving a 1 in 43 quintillion puzzle in 7 seconds - but whether it takes minutes, hours or days, the Rubik's Cube is still the king of un-putdownable puzzles. Are you up to the challenge?