4 cups water
3 (3 ounce) packages grape-flavored gelatin mix (such as Jello-O®)
2 cups white sugar
1 (12 ounce) can frozen lemonade concentrate
48 ounces pineapple juice
1 ounce almond extract
2 gallons water, divided
2 (2 liter) bottles ginger ale
Combine 4 cups water and gelatin mix together in a large pot; bring to a boil and stir until gelatin dissolves. Add sugar, lemonade concentrate, pineapple juice, and almond extract, respectively, stirring well after each addition.
Divide gelatin mixture between two large freezer-safe containers. Pour 1 gallon water into each container, stir to combine, cover each container with a lid, and freeze until set, 8 hours to overnight.
Remove containers from freezer and break each block of gelatin mixture into chunks. Pour contents of each container into separate punch bowls and pour 1 liter ginger ale over frozen mixture into each bowl. Stir until punch is slushy and combined.