Here's an interesting idea from Israel-based ST Microelectronics: A ring that can be used as a pointing device, switch, or control.

MicroPointing's miniature pointing and digital control device has greater capabilities than the touchpad, while requiring only a tiny fraction of the space - approximately 1 sq. mm. This electronic tracking device can also be used as a switch or control, enabling mobile product producers to replace larger buttons and mechanical switches.

- Pointing device/mouse is the smallest of its kind currently available, with no mechanical moving parts - Operation is user friendly, easy, comfortable and does not necessitate small fingers for accurate use - Small footprint device can be used in several physical configurations, adjusted

The company has not named the precise product application, but it would be neat as a finger-tracking replacement for the desktop mouse. And I'd love to have one of these wirelessly connected to an MP3 player as a volume control and play/pause button.