Bring water and white granulated sugar to a boil in a saucepan. Boil for 15 minutes, then remove from heat and allow to cool. Stir in gin, iced tea, lemonade, and lime juice. Pour into a plastic container and freeze overnight. To serve, scoop out about one cup of the slush mixture and put into a collins glass. Top with a spritz of club soda and garnish with a mint leaf. Makes 15 servings.Courtesy of Bud & Marilyn's in Philadelphia.