There is a game played in most of the world called Mancala. It is a “count and capture” game that involves moving stones around a board made up of holes. You can see an explanation of various forms of rules of the game here.
Ireland has some of the best preserved ancient tombs and building sin the world. This means we have some of the oldest known versions of games in the world. Boards of a game called “windmill” have been cut into the temple at Kurna, Egypt (~1440 BC). A version of this game called “Nine Man Morris” is still played. Tic Tac Toe can be considered a very basic version of it also. The earliest known depiction of this game is a bronze age cemetery in Ballinderry Ireland.
Boards of nine man morris have also been found in roman age sites.
Irish 5000 years old Mancala boards should look like this. On a flat surface. Two rows of holes, probably six holes (possibly more) long with slightly larger holes at either end. Possibly you would see a few together as mancala is currently a social game and tends to be played in groups.
We tend to view megalithic carvings as having a religious purpose. It is quite possible that megaliths were gathering points and as such social games took place there. So next time your at a megalith have a look for a game board.