The Pentagon invites you to play its red balloon game

From this morning (5th of December), people across the US will start hunting for 10 weather balloons hidden across the country by the Pentagon's research agency DARPA.
The treasure hunt is designed to test how well people can coordinate with one another online and will award $40,000 to the first person to enter the GPS coordinates of all 10 balloons, accurate to within a mile. The 2.5-metre-diameter tethered balloons will be flown only in daylight, and taken down for the night.

Full story by MacGregor Campbell on New Scientist