The US government's Sandia National Laboratories has built what it describes as the world's smallest autonomous, untethered robot. Weighing less than an ounce, it is only 1/4 cubic inch and powered by three watch batteries. It has an 8K ROM processor, a temperature sensor, and two motors that drive its tank-like tracks. Among accessories under consideration are a miniature camera, microphone, communication device, and chemical micro-sensor.

For more information, read sandia.gov and beyond2000.