A ball is thrown at a number of pins standing side by side.
Image needed?
The size of the ball is such that it can knock down either a single pin or two pins standing next to each other.
Players take it in turns to roll the ball.
The person who knocks over the last pin (or pair of pins) wins.
Try to find a winning strategy (assume that you always hit the pin or pins that you aim for and no one is ever allowed to miss).
Now try changing the rules ...