GyroSpin

I've always wanted to make gyroscope to demonstrate physics to my children. But machining such thing is out of my skills, so I've tried printed one.
https://youtu.be/XxwsAl4LSag

You will need 5 pieces of steal bearing balls ( 9.5mm diameter )

Outer rings could be printed all at once without any supports.

Center wheel needs supports "from platform only" and rotation axis has to be oriented horizontaly (see screenshot in photos)

EDIT1: Added centerWheel for 8 balls
EDIT2: Added separated rings - in case your printer is not capable of printing them all together.