Like Sudoku Online, this one was born out of a simple thought - "I wonder if this is possible..." I was studying Chess algorithms, and I realized that it was possible for a computer to track moves. At the time, the only real "programming language" I knew was MATLAB®, so I got to work, and wrote the first Chess Player for MATLAB.
Supported wherever MATLAB GUIs are supported, the app will track player moves and keep a log of them, which can be docked or free-floating. It also ensures that checkmate is valid, and won't let the player put his or her King into harm's way. The game highlights squares that are valid moves, albeit using an inefficient algorithm. But at the end of the day, it works, and it taught me a good bit about MATLAB®.