width=350The competitive types like me might enjoy the Power Ball. It's described on the I Want One Of Those site like this:

The top speed possible is 15,000 rpm - though we've never made it past 12,000 (wimps), and it exerts the most remarkable forces on your wrist - you really feel like you've had an arm workout! Playing with this is an almost guaranteed crowd puller, as everyone will want a go, and be determined to beat everyone else's highest score.