We have recently bought a new style Gyration keyboard and mouse for use in assemblies or presentations. The mouse is quite different to the old design in that it looks like a TV remote control. The gyrascope is built into the hand held device. It has multimedia controls aswell as small left & right mouse buttons which can be operated without a surface. The keyboard also has internet and media controls. Both devices are radio controlled via the USB dongle. They both take AAA batteries which will last about 12 months. I have found this equipment very useful in our school hall as it allows the presenter to stand well away from the computer and projector. They have a 10 metre range.
Find out more from the GYRATION website
Each set of equipment costs about £100. It is worth shopping around various IT companies..