3 cloves garlic, minced
2 teaspoons butter
1 cup Heinz ketchup (a must for us)
1/4 cup packed brown sugar
1/4 cup chili sauce (Heinz is a good one)
2 tablespoons Worcestershire sauce
1/2-3/4 tablespoon celery seed
1 tablespoon prepared mustard
1/2 teaspoon salt
2 dashes hot pepper sauce
8 large chicken breast halves, bone-in with skin (a large family pack will usually have about 7-8 breasts.)

1  In a saucepan, saute the garlic in butter until tender.
2  Add the next 8 ingredients.
3  Bring to a boil, stirring constantly.
4  Remove from the heat and set aside.
5  Grill the chicken, covered over medium heat for 30 minutes, turning occasionally.
6  Baste with sauce.
7  Grill 15 minutes longer or until juices run clear.
8  Continue basting and turning during the last 15 minutes of cooking.
9  Serve with any extra sauce you set aside for dipping.
10  (The sauce is just that delicious!).

source:  http://www.food.com/recipe/best-ever-bbq-chicken-88453