FREEZE watermelon in a shallow pan at least 6 hours
COMBINE frozen watermelon, rum, lime juice, and orange liqueur in containter of electric blender.
BLEND until smooth, scraping down sides once.
ADD enough ice to bring mixture to 5-cup level.
BLEND until smooth.
Repeat procedure, if necessary, until mixture measures five cups.
Per Serving (excluding unknown items): 136 Calories; 1g Fat (7.7% calories from fat); 1g Protein; 14g Carbohydrate; 1g Dietary Fiber; 0mg Cholesterol; 3mg Sodium. Exchanges: 1/2 Fruit.