Heat in a large (12-inch) skillet, 3-4 tablespoons of olive oil. Add onions and celery, cooking for 6 minutes. Add cubed eggplant. Cook for 12 minutes stirring occasionally. Add remainder of olive oil a little at a time during the 12 minutes. Stir in crushed tomatoes, capers, basil, red wine vinegar, sugar, salt, and pepper. Simmer until all vegetables are fork tender, about 20 minutes, stirring occasionally. Spoon mixture into large bowl and add black and green olives. Serve mixture warm or at room temperature. Refrigerate remaining caponata. Serve with pasta, rice or crustini (toasted baguette.) Note: Make at least one day in advance of serving. Mixture can be frozen in large batches.