Logitech Marble Mouse - good trackball at low price

I found this trackball mouse at radio shack on clearance for just $15.
It's a great little trackball. It spins pretty well. Good deal.

Now I just need something to function as a spinner...

dos-man

Trackballs make pretty good spinners with the same type of control if
you're good with them. You can just use left and right spins, but what
I did for a game like Gyruss is spin around the edge (fingers starting
at top) which might be better for something like Tempest.

Hope this helps...