Tag and hide and go seek are lots of fun for kids. No supplies necessary, just a few rules required, such as boundaries. Some consideration has to be given for players significantly younger than the others too.
These are best with a crowd of kids, not just a couple. Three is pretty much a minimum, all the way up to however many can agree on the rules of the game.
Indoor hide and go seek requires some extra rules, of course. Sometimes we’ll limit it to downstairs only, so there’s no one running down the stairs; other times the rule is just “stay out of mom and dad’s room.