In the late 90s I gave this toy to my nephews when they were about 10 and 7. It's referred to as a Gyro Ring Toy. Found it at some science toys store. There's also a version with larger colored plastic rings with an inner steel or brass part contacting the larger ring, that one is also still available. I got them one of each. They went nuts for it. Odd phenomenon, when you get the small rings spinning fast enough, they shimmy slowly down the ring as you turn it, making it vibrate.
Gyro Ring - High Performance Version - Science Bob Store
May not sound like much but I showed it to the guys at work just before Christmas and they all got a kick out of it. Takes a bit of practice to get the brass washer/ring things to spin fast enough for the phenomenon to take off, so once my nephews got it down, they showed it to all their friends who couldn't make it work w/o coaching from the nephews which made them into temporary big shots. And I, of course, was briefly a big shot with my nephews until they could get it working. In fact, I almost didn't even consider buying it at the store as I couldn't get it to do anything just from the packaging instructions. One of the employees demonstrated it for me.
This vid shows how to start it. He first tries squeezing it with the thumb and sort of popping them in a spinning motion. That's the best way I found, looks more cool than the second way he did it, where you try to fan them rapidly:
https://www.youtube.com/watch?v=DP86woa8Ue0