If you're not familiar with Recent Toys' collection of fun and creative brain-teasers, go search them out online.  Today, I'm looking at Brainstring Advanced.  This perplexing-looking plastic ball has a simple goal -  but a time-consuming solution, one which will test your visualization skills and concentration.  The idea is to get the pegs of like colors all on the same side of the ball, with all of the strings that stretch across the interior untangled and pulling straight through the ball to pegs on the opposite side.  How complicated you make it is up to you, based on how much you tangle up the "innards" before beginning.  Fun - if you have the patience for it!