Reserve 4 raspberries and cut off 4 slices of lemon for the garnish. Mash the raspberries and sugar in a small bowl and let sit at room temperature to thaw and bring out their juices, about 15 minutes. Set a sieve over a pitcher and juice the lemons. Rinse the sieve and add the raspberries. Push the raspberry mixture through the sieve with a rubber spatula, leaving the seeds in the sieve. Pour 1 quart of cold water through the sieve to get remove the remaining juices. Stir the lemonade and check for sweetness. Serve in ice-filled glasses and garnish with raspberry and a lemon slice. For the adults, add 1 1/2 ounces vodka to each glass.