Poll: What's the Perfect Large-Group Game?

The season of reunions and holiday get togethers is here. And so is the quest for the perfect large-group game or activity. You need one that engages all ages, one that helps long-lost cousins get to know each other. And of course, it has to be fun, something you'll talk about until the next year. Does such a game exist?
What's your favorite?
Let's us konw. Everyone who comments within the next seven days will be put in a drawing for a prize.