From the outside, it looks like an oversized convenience store. But the towering stacks of unopened snack boxes spilling onto the sidewalk, and employees hauling cartons inside from morning until night, suggest something unusual is going on. Mascots for Busy for You (left) and Super Ming (right). By late afternoon, crowds begin to form. First come elementary school children in red scarves and school uniforms, clutching pocket money as they line up for snacks. Then middle and high school st