When it comes to entertaining, Daniel Boulud has a lot of impressive tricks up his well-tailored sleeve. But at a recent dinner party he dazzled the crowd with something that had zero to do with high-end gastronomy and everything to do with playful fun and ingenious why-didn't-I-think-of-that practicality: kids' water balloons, filled and frozen. Et voilà—perfectly formed ice balls. No expensive gear required, easy to make for a crowd, and ready to peel for cocktail time. Well played, chef.