Sudokuto
Sudoku with a twist.
Sudokuto is a game for two — here you play the computer. The board starts empty, and you take turns placing one legal sudoku number each. The winner completes a row, column or box, or makes the last legal move. Place an illegal number and you lose.
The game also works anywhere with pen and paper: draw an empty sudoku board and play by the same rules. Sudokuto was invented on 16 June 2005.