A mock-up of the classic [Minesweeper](http://en.wikipedia.org/wiki/Minesweeper_(video_game\)).
After selecting the size of the square board (bigger is more difficult), and the number of mines (more is more difficult), the player reveals or flags the hidden cells of the board one at a time.
If a bomb is revealed, the game ends. If a cell adjacent to a bomb is revealed, a number is displayed that indicates how many bombs are adjacent to that cell. If a revealed cell is not adjacent to any bomb, all its adjacent cells are revealed; this proceeds iteratively, until all revealed cells are either surrounded by revealed cells, or have an adjacent bomb. Then, control is passed back to the player.
Unrevealed cells can be flagged as containing a bomb. The player wins when all bombs are flagged, and all other cells are revealed.
The game state can be saved or loaded as a text file. It is, unfortunately, fairly easy to cheat by examining the save file.