Ball Bearings are very useful for things that must be supported and spin at the same time. This tutorial gives a how-to on making a ball bearing in Blender 2.6.
Step 1: First Circle
Blender is a free, powerful, 3D modeling program. If you have not already downloaded and installed it, do so.
Open blender and delete the default object. (Keep the camera and light if you want to render)
Click Add => Mesh => Circle. On the lower left panel you should see "Add Circle". Make this circle have 36 verticies and any radius.