Tag is a very simple and very popular game. One person starts out as "it," and they try to chase down the other players and touch or "tag" one. That person then becomes "it" but they can't tag back the person who just tagged them. There are rules to every tag game, of course, like the idea of safe zones. If a certain player is touching an object, like a tree, or on the grass or pavement, they're safe from tagging.