In a 12-inch skillet, cook bacon until crisp. Drain on paper towels reserving 3 tablespoons drippings in skillet.
Meanwhile, halve 2 cups of the grapes.
Add vinegar, brown sugar, salt and pepper to skillet. Heat 30 seconds just until warm.
In a large bowl combine spinach, and halved grapes; add warm drippings mixture. Toss to coat. Divide among 4 plates. Top with cheese and bacon. Serve with remaining grapes and pecans. Makes 4 servings.