Charleston-area runners have their favorite routes: Mt. Pleasant to Charleston and back over the bridge, loops around Hampton Park, or Sullivan's Island to Isle of Palms. But you rarely see them schlepping up and down the King Street Extension. In its second year, the Charleston Marathon once again channeled hordes of sweaty people in short shorts from the peninsula to North Charleston, a route that necessitated a good, long romp through the part of town known as the Neck. And it got some of them thinking: Why not run this route all the time? The traffic is mild, there's plenty of easy-on-the-knees grassy terrain beside the road, and on top of that you get a pleasant tour of the area's warehouse-and-strip-club district. It also got them thinking about how the peninsula is shaped sort of like a horse head, so why not call the streets leading out of it the Unicorn Horn?