Formally known as Mousercise. One of the most widely used mouse tutorials in the world. Spanish language version is also available.

With heavy usage, the accuracy of the common computer mouse begins to degrade with time. Household dust and dirt floating through the air tend to settle everywhere including the innocent mouse pad sitting next to your personal computer.

A fascinating article that describes how your computer mouse works. (HowStuffWorks)

We all have one and need one, what's with these little furless creatures? The mouse is a common part of the PC and would be hard to get along without.