Cook and stir ground beef, onion and garlic in large nonstick skillet over medium-high heat until beef is browned and onion is tender.
Drain and discard fat.
Combine ketchup, bell pepper, Worcestershire sauce, sugar, mustard, vinegar and chili powder in 4 1/2-quart slow cooker. Stir in beef mixture. Cover; cook on LOW 6 to 8 hours. To serve, spoon mixture onto hamburger buns.
You can precook the ground beef and store in freezer bags for quicker meals. You can also freeze leftovers for another fast and time friendly meal