Put a colander or strainer in a bowl. Pour cherries into the strainer. Measure out 3 tablespoons of cherry juice and put it in a small container. You will use these 3 tablespoons of juice to prepare this recipe. You can either discard the remaining juice or save it for another use.
Put cherries from the strainer onto a cutting board. With a sharp knife, carefully cut cherries into small pieces. Have an adult show you how to use the knife.
Put chopped cherries, 3 tablespoons juice and ice cream in the container of an electric blender or food processor; cover blender. Process or blend until smooth. Do not put a spoon or spatula in the blender while it is running and keep your hands clear of the working parts.
Pour into 2 (12-ounce) glasses. Top with whipped topping; garnish with whole maraschino cherries.