Averso
Avverso is a minimalist abstract-connection game with a game board comprising only 25 hexagons. (For comparison, Nobel laureate John Nash claimed 14×14 to be the optimal size for a Hex board.)
In Avverso, each player is trying to connect opposite sides of the game board with a chain of stones in their color – but when you add stones to the board, you add stones of the opponent’s color, not your own! On a turn, you slide one of the opponent’s stones into one of the outer hexagons of the board. If necessary, you push one or more stones already on the board to make room for the new one. By pushing stones into new positions, you can drastically change the situation on the board, hopefully to your advantage.
The board is non-symmetric, and the shape balances the disadvantage of starting, making Avverso a well-balanced game in addition to being quick and dramatic and requiring deep thought.