I believe intensive use of mouse can cause a condition called carpaltunnelsyndrome.
To prevent that, I've built a "device" out of duct tape, neodym magnets and a rather broad variety of rubber band, whose name I don't know in English. In Finnish it's called "kalsarin-kumi[coo-me]-nauha[now-huh]" (underware['s]-rubber-band). You can see the material, and a ready-to-use "device" here (on a lousy Yamaha amplifier): http://www.gypsii.com/place.cgi?op=view&id=116371
