Jose Daniel Zapata Arisrizabal, of Colombia, practices during an Olympic qualifying skateboarding event at Lauridsen Skatepark, May 19, in Des Moines, Iowa. (AP Photo) DES MOINES, Iowa--The hotel door opens and, fast as that, the sound of polyurethane clicking across concrete begins. The rhythmic grrrr-chk-chk-grrrr-chk-chk-grrrr-chk-chk sound of wheels scooting over cracks in the sidewalk is a telltale sign that something is different in Des Moines. Skateboarders have taken over Middle America this week. It’s a dress rehearsal for this summer, when they’ll bring their show to the rest of the world at the Olympics. The questions under the magnifying glass at this week’s Dew Tour--one of the last major qualifying events for the Tokyo Games in July--are whether the Olympics is ready for skateboarding and, more tellingly, whether skateboarding is ready for the Olympics.