Tell your kids that you're going to see who can get ready first. Then ask, "What do you need to get ready for swimming?" Have them find something needed for swimming (swimsuit, goggles, etc.) and bring it to you as fast as they can. Then repeat the game with items needed to get ready for school, soccer practice and so on.
Explain that it's important to be prepared. That's why God sent John the Baptist to help people get ready for the coming Savior. Many people came to John to be baptized, confessing their sins and preparing their hearts for Jesus.