Yote

Yote is a game played widely in West Africa, especially in Senegal, Mali, and Burkina Faso. It's at least 200 years old and closely related to other African games. Pieces start off the board, but either of the two players may place, move, or capture pieces on any turn. All moves and captures are orthogonal, not diagonal. The exciting bit is that when a piece is captured by a short jump, the capturing player may remove any other piece on the board. So a capture means that two pieces are lost. As you can expect, this can change the balance of the game in a hurry! For even more excitement, some variants allow chain jumping, and another variant allows players to jump their own pieces without consequence. Yote is fast and hard to predict, and it is said that feverish betting on the outcome of a game is not unusual.