1. Prepare grill.
2. Combine first 9 ingredients in a large zip-top plastic bag. Add pineapple, and chill 1 hour, turning occasionally.
3. Remove pineapple from bag, reserving marinade. Place pineapple on a grill rack coated with cooking spray, and grill 4 minutes on each side or until thoroughly heated, brushing with reserved marinade.
4. Arrange 2 pineapple slices on each of 4 dessert plates; top each with 1/3 cup ice cream. Drizzle any remaining marinade over ice cream.