Blogger Dumb Little Man says that being ambidextrous with the mouse can increase your brain power:
By switching the side of your mouse-pad you will force yourself to use your non-dominant hand. This, in turn, will stimulate the neural connections between the right and left hemispheres on your brain. Scientific research confirmed that people that use both hands equally have 10% more nerve fibers joining the two sides of the brain.
Mousing "goofy" can also help you stop RSI. Here's how to train yourself to mouse with the other hand.