Three games with horses.
The first one is a simple race: choose a horse and hope he wins. Children as young as two enjoy this game. Two of my testers, aged 5 and 7, have found a clever way to play.
The second game is a race for one player against the clock or two players. It requires thinking and planning. An intuitive or acquired knowledge of geometry doesn’t hurt.
The third game is an old chess puzzle, the Knight’s Tour. You can play at random with little chance of success, or try your hand at H. C. von Warnsdoff 1823 heuristic, which also involves some thinking and planning.