One of the simplest ways to reinvent an ordinary dinner or leftover food is to add a sauce. The types of sauces and ways to use them are infinite. Use a sauce on meat, poultry and pork to add flavor and moisture, or on vegetables to make what is a typical side dish an unusual complement to your meal. The right sauce on angel food cake and fruit marries the two and merges the flavors and textures. Sauces are easy to make ahead and keep on hand for meals in your refrigerator or freezer and will come especially in handy for unexpected company or a hectic weeknight when you don’t have time to create a meal from scratch. When you share your sauce recipes here, please tell us how you use them. And don’t forget your best barbecue sauces.