Stir sugar and water in small saucepan over heat, without boiling, until sugar dissolves. Bring to a boil. Boil, uncovered, without stirring about 5 minutes or until syrup thickens slightly. Remove from heat and cool to room temperature. Stir in rind, juice and Campari.

Pour mixture into a shallow cake pan. Cover with foil and freeze about 3 hours or until almost set.

Using a fork, scrape granita from bottom and sides of pan, mixing frozen with unfrozen mixture. Cover and return to freezer. Repeat process every hour for about 4 hours or until large ice crystals form and granita has a dry, shard-like appearance.

Serve granita in individual serving glasses.