I got this recipe from the Best Loved Slow Cooker Recipes Cookbook! I highly recommend them too!
3 lbs ground beef
1 cup chopped onions
3 cloves garlic, minced
1 1/4 cups of ketchup
1 cup chopped green bell pepper
1/4 cup plus 1 tbs Worcestershire sauce
1/4 cup packed dark brown sugar
3 tbs mustard
3 tbs vinegar
2 tsp chili powder
Cook & stir ground beef, onion, garlic in a large skillet over medium-high heat until beef is browned and onion is tender. Drain & discard fat.
Combine ketchup, bell pepper, Worcestershire sauce, sugar, mustard, vinegar, and chili powder in the Crock Pot. Stir in beef mixture. Cover and cook on low for 6 - 8 hours.
Spoon mixture onto buns & enjoy!