Windows 7 - How do I make Windows 7 desktop gadgets visible on mouse-over only?

With Microsoft Windows 7 desktop gadgets, people either love them or hate them. Those that love them feel the various gadgets add features to the desktop that the standard desktop doesn’t offer. Those that hate them feel like the gadgets only get in the way of a working desktop. For the latter users there is a way to use gadgets and keep them out of the way until you mouse over the area of the gadget. This will allow you to take advantage of gadgets without letting them cluttering up your desktop. By default you can make a Windows desktop gadget visible and you can even change the opacity of a viewable gadget. When you set a gadget to a less-than-100-percent opacity a mouse-over will bring that gadget back to 100%. With that in mind, you would think it possible to set a gadget’s opacity to 0% and then see the gadget with a mouse-over. The problem is that the lowest opacity offered is 20%. So how is this done?
In this How do I article I am going to show you how to get those gadgets to 0% opacity which will then revert to 100% upon mouse-over.