If you see any large red balloons in the sky this weekend, please let us know.

No, this isn't a part of an elaborate hoax perpetrated by would-be reality TV contestants. It's part of a contest, sponsored by the Defense Advanced Research Projects Agency (DARPA), marking the 40th anniversary of the Internet.

In the DARPA Network Challenge, ten red balloons will be in fixed locations around the United States on Saturday, December 5. Several research scientists in the Georgia Tech Research Institute have accepted the challenge, and are asking the Tech community to help them in the cause.

The first team to correctly identify the longitude and latitude of all ten will win $40,000, an award the Georgia Tech team - nicknamed "I Spy A Red Balloon" - has pledged to donate to the American Red Cross.

This competition is designed to explore the roles the Internet and social networking play in the timely communication, wide-area team-building, and urgent mobilization necessary for solving broad-scope, time-critical problems. Ethan Trewhitt, a member of the Georgia Tech team, said the DARPA test will underscore the features and idiosyncrasies of these networks as information on balloon sightings, both legitimate and falsified, begin to spread.

"Twitter, for example, is often the fastest avenue for discovering breaking news events like an earthquake or the death of a celebrity, but its lack of authority makes it difficult to tell fact from rumor," he said. "The contest represents an effort by DARPA to see how the Internet can react quickly to a news event."

Trewhitt's team is currently in network building mode, creating a Facebook group and Web site (below) to solicit volunteers. On Saturday, the team will then switch to data collection mode, culling information both from their volunteers and from passive mentions collected on the day of the event.