Combine:

2 tbsp. vinegar
1 tsp. salt
1/4 tsp. pepper
1 tbsp. sugar
2 tbsp. Worcestershire sauce
3/4 c. ketchup
1 tsp. chili powder
1 tsp. paprika
1/4 c. water

Place 1 1/2 pounds hamburger in casserole. Pour sauce over. Cook in oven 15 minutes, uncovered at 375 degrees. Stir well. Reduce heat to 325 degrees, continue cooking uncovered for 1 hour.