I have a toy which consists of 5 quarter-inch-thick, colorful plastic washers on a metal hoop about a foot across. You strike the washers with one hand to start them spinning, then rotate the hoop with your other hand; for reasons I still don't understand to my satsifaction, the washers keep spinning and can be made to "float" up and down the hoop. I had a friend with one of these a long time ago; I eventually stumbled across one in a some sort of junk shop, but still don't know what it's called or where I'd find another one. And googling variations on "ring toy" doesn't get me too far.

I call it magic!

Like this?

No, like this! Eureka! I'm glad to see the physics are apparently nontrivial, too.

It went zip when it moved and pop when it stopped, whirr when it stood still. I never knew just what it was and I guess I never will.

I used to have one of those! Yay! boo for nasty formulae though