Even as an adult, I still enjoy playing with puzzle games, and buckyballs are no exception to that:
Named after R. Buckminster Fuller, inventor of the geodesic dome. “BuckyBall” is the nickname for a Carbon 60 molecule. Each set contains 216 neodymium magnets that can be shaped, molded, torn apart and snapped together in unlimited ways. Make sculptures, puzzles, patterns, shapes, stick stuff to the fridge. Imagine a Rubik’s Cube that actually makes you smarter; an Erector Set that never stops erecting; a Hula Hoop you don’t look ridiculous playing with; Silly Putty that isn’t silly; cram it all in a jar, turn the fun up to 11, and you’ve got BuckyBalls!
Warning: Oh, and just in case, this is a toy for adults only. Amazon says that Buckyballs should not be given to kids under 14 years of age.
Edit: Just stumbled on a much cheaper product that does exactly the same thing: [Neocube – $16.95 on Amazon.com]