In a 3-quart plastic freezer container combine apricot nectar, pineapple juice, orange juice concentrate, and lemonade concentrate. Seal and freeze at least 24 hours or up to 1 week.
To serve, let frozen mixture stand at room temperature for 30 minutes. Scrape into a slush. For each serving, fill a glass 2/3 full with slush. Carefully add ginger ale, stirring gently to mix. Garnish with apricot slice, if desired. Makes about 24 servings.