This fruity drink is perfect for a summer party.
Make a simple syrup: Combine the water and sugar in a large saucepan, and bring to a boil over medium-high heat. Cook 5 minutes. Remove from heat, and set aside until syrup is completely cool.
Transfer syrup to a large container. Add strawberries, pineapple, pineapple juice, orange juice, and lemon juice; gently stir to combine. Fill two ice-cube trays with punch, and place in freezer. Place remaining punch in refrigerator to chill.
When ready to serve, remove punch from refrigerator; add the seltzer water and frozen-punch ice cubes. If transporting, add the seltzer just before serving. Serve in a large bowl or individual glasses.
The punch can be transported to the party in a large thermos or in several containers placed in a cooler until ready to serve, if necessary.