Ever since the days of the IBM PC Jr., many users have insisted on wireless input devices. The demand has increased with PC presentations because it is much more difficult to run a live presentation from a notebook computer than it is to switch slides or transparencies.
Some wireless mice have gyroscopes to broadcast position information.
This is cool, but use them in the midst of a presentation, and you might look like you are swatting at flies. Wireless Computing Inc.'s SurfMouse is not really a mouse but rather a simple two-button touchpad. You run a presentation holding the device in one hand, which leaves the other free to hold notes or gesture in emphasis. I found several ergonomic problems with the SurfMouse. It's a little large for small or medium-sized hands, and it works upside down.