Got this recipe from Real Simple and here is a pic from last summer!
4 cloves garlic, chopped
2 tablespoons brown sugar
1 teaspoon chili powder
1/2 teaspoon cayenne pepper
salt and pepper
2 racks baby-back ribs (about 3 pounds)
In a small bowl, combine the garlic, brown sugar, chili powder, cayenne, 2 teaspoons salt, and ¾ teaspoon black pepper.
Rub the spice mixture on the ribs and let sit for 10 minutes. Meanwhile, heat grill to medium.
Grill the ribs, covered, turning occasionally until cooked through, 25 to 30 minutes.