This afternoon, 430 students at Robeson Elementary will hoof it around the school in its first fundraising walk-a-thon. The goal: $100,000 to replace and repair a playground beset by drainage issues. JESSICA PITCHER, principal at Robeson Elementary in Champaign, dreads the mornings when she has to announce to her students that the mud pit of a playground is off limits because the weather's yucky. "When they hear that they can't go outside or the words 'blacktop only,' you can literally hear the groans," she said.