This toy is cheap and easy to make yet irresistible to ferrets.  You need:

1. a wooden or metal box that’s slightly wider than your ferret and as long or longer than your ferret
2. large marbles – too large to swallow

My ferrets love to roll marbles around on the wood floor – it makes noise and they like to chase things.  If you’ve ever seen a ferret curl up in a baseball cap or a bowl, you’ll know how the box part works.  First, it has to be wooden or metal so the marbles make the required noise that ferrets love.  Second, it should leave the ferret enough room to roll and squish his body around in, yet small enough so he feels the box on all sides when he’s squirming.

Put ferret and marbles in box, and voila- he’ll writhe around on his back, grab the marbles otter-like and eve hold them in his hands, crystal ball- like, resting on stomach.  Have fun!