[concretegurl]

So many people here listed fetch and this came to mind, I should say I'd honestly be a little concerned over safety with a dog being unsupervised with this, but I'm sure some safety measures could be taken...this guy built this himself and doesn't seem to sell them that I can find...this is just such a kewl idea to me though for the never ending game of fetch, my arm gets tired after awhile with three here.
Self entertainment at it's best and obviously a little training to get Jerry or any dog to do this themselves.

YouTube - Jerry needs no help playing with his...