In a large skillet over medium heat, brown the ground beef for about 5-7 minutes, breaking it apart as it cooks. Drain excess fat if necessary.

Add the chopped onion and green bell pepper to the skillet with the cooked beef. Sauté for 3-4 minutes until softened.

Reduce heat to low, then stir in ketchup, Worcestershire sauce, and brown sugar. Simmer for about 5 minutes.

Adjust seasoning with salt and pepper as needed.

Serve generous portions of the mixture on toasted hamburger buns.