There are two kinds of calzone, and they both come from Southern Italy. calzone in Italian is a funny word, because calzoni means "trousers", so a calzone would be one trouser leg. Anyway, back to the food:
  1. the fried calzone is a disc of dough that is filled with mozzarella cheese and tomato sauce, folded, and deep fried. I have had these in Puglia. They should be eaten hot.
  2. the baked calzone is basically a large pizza (in the Italian concept of pizza), folded in two and baked in a pizza oven.
    Now quite frequent in pizzerias all over Italy.