Warm large skillet. Ad ground beef and onion. Cook for 10 minutes or til ground beef is crumbly and no longer pink. Stir frequently; drain.
Stir in ketchups, vinegar, lemon juice, Worcestershire, mustard, paprika and brown sugar. Season with salt and pepper. Cook uncovered, over low heat for 30 minutes or til thickened, stirring occasionally. Divide mixture among the hamburger buns. May serve with cheese. Serves 4