One of the most delicious (and educational!) aspects of the forthcoming New Orleans Roadfood Festival is the opportunity to compare and contrast different variations on culinary themes, foremost among them barbecue. This year, the Louie Mueller rolling pit will be serving Texas beef in the form of brisket and sausage, and Central Barbecue is coming from Memphis with pork in the form of ribs and pig sandwiches. Zesty sauce and cole slaw are essential elements of a pig sandwich (pictured above, as made by Central Barbecue), but in Texas smoke parlors, they are about as welcome as ketchup on a Chicago hot dog.