Exploding from the other end of the field, a silver robot glinted under the light of the cameras and burst toward the lone defender standing between it and the goal. But suddenly, the robot stopped dead in its tracks, hopelessly mired as if it were stuck on superglue.

A metal arm appeared to rescue the wayward robot, but it was no crane--it was an acupuncture needle. And the field it plucked the robot from was hardly the size of a grain of rice. What do you expect when the robot is six times smaller than an amoeba and weighs no more than a few hundred nanograms?

Robots of all sizes have descended on the campus of Georgia Tech for <A HREF="http://news.yahoo.com/s/ap/20070707/ap_on_re_us/nano_cup">the RoboCup, an international contest</A> that pits robotic creations against one another in a range of technical challenges. But perhaps the most intriguing event was Saturday's Nano Cup, a competition hailed by organizers as the world's first nanoscale soccer game.

Held by the National Institute of Standards and Technology, its organizers hope to show the potential for building tiny devices that can be used in manufacturing, biotechnology and other industries. They also hope to develop manufacturing standards for the untapped field.