 Summer is the time for the best outdoor cooking, so it's no surprise July is National Grilling Month. Man has been cooking over an open fire since the domestication of fire. But while grilling is popular today, it wasn't until after World War II and people moving out of the cities that the backyard grill became popular. You can cook just about anything on a grill, from burgers to watermelon. But remember to do it right. Keep your grill clean and always preheat when you're grilling.