As if fulfilling a child’s fantasy, 43 robotic vehicles began racing around the California Speedway in a government-sponsored test of artificially intelligent machines. The winner will take home $2 million. The race is the second annual DARPA (Defense Advanced Research Projects Agency) Grand Challenge, a U.S. military-sponsored desert race that tests the endurance of robots. It’s a challenge that taps the creativity, brain power, and funds of U.S. universities and private-sector visionaries as the military tries to push the envelope of artificial-intelligence technology.