Mix ingredients in large punch bowl. Fill punch glasses with ice and ladle punch into glasses. Top each glass with a splash of ginger beer and a dash of ground cinnamon. Float an apple slice as garnish.
In a saucepan bring water and sugar to a boil and let boil for 15 minutes. Remove from stove and allow to cool. Add remaining ingredients and stir well. Pour into a plastic container and freeze overnight. To serve, using an ice cream scoop, scoop slush into a martini glass and top with lemon-lime soda. Makes 30 drinks