I have an extra ball for my CST trackball on my desk, and I decided to design a nice 3D printed stand for it. It uses a standard skateboard bearing and you can make the ball spin for a very long time (and by that annoy your colleagues endlessly).
You can find the files for this model here: https://www.printables.com/model/301938-billiardpool-ball-stand-with-a-ball-bearing
