To make this delicious treat, oil your grill rack with a paper towel dampened with vegetable oil. Then prepare the fruit: Cut peaches, nectarines or plums in half and pit them. You can use the halves or cut them into chunks. Core pineapple, peel it and then slice it into chunks. (Or use fresh pineapple that's already been peeled and cored, available in the produce section.) Larger fruit can be placed on the grill racks, but smaller fruit, such as thick banana slices and grapes, should be threaded onto bamboo or metal skewers. Grill until the fruit is just lightly marked and warmed through. Try serving it, still warm, over ice cream-yum!