The unique citywide racing adventure Urban Challenge makes its debut in Raleigh this Saturday, Aug. 24. With its hidden race course, Urban Challenge forces participants to think on the run, answering trivia questions to qualify for strong starting positions, deciphering clues that could reveal correct checkpoints, and keeping an eye out for the elusive "Skip Man," who can give them an edge over their opponents. On race day, 300 two-person teams will gather at Jillian's in Raleigh, where they will be provided with a list of clues to 12 checkpoints throughout the city that they must visit and be photographed at in correct order before racing back to the finish line. Once on the road, racers can run or take advantage of the city's public transportation system. The first team back wins. For "clues" to the event, call 876-1311.