Xpuyopuyo is a Tetris-like game in which the object is to match four or more blocks of the same color. Multiple matches are worth more points, and result in rocks being dumped on the opponent. It supports human-human, human-AI, AI-AI, or network game play, and a number of gameplay options including themes and music. The game also features AIs that can learn to play strategically.
PyTraffic is a Python version of the board game Rush Hour created by Binary Arts Coporation. The goal is to remove the red car out of the grid through the slot on the right. To do this you have to slide the other cars out of the way. PyTraffic comes with about 19,000 puzzles ranging from intermediate to expert, and has an extremely smart hint facility which is able to find the best move in every position.
The Z-machine Preservation Project is a Java implementation of the Z-machine (Java version >= 5 is required) specification. This Z-code interpreter can be run either as a standalone application or as an applet within a Web browser. It runs Interactive Fiction created by Infocom as well as those compiled with Inform, and targets all existing story file versions. Features include saving the game state, multimedia support (graphics, sound effects, meta data), colored and styled text, undo, and timed input as well as support for different languages. Games in the Inform 7 release format are supported as well (Treaty of Babel specification).
3Doku brings the traditional Sudoku game to the third dimension. In a 9x9x9 cube, 27 Sudoku schemas intersect one another along the three axis. Every 9x9 bi-dimensional schema must be solved, keeping in mind that every single cell belongs to the selected schema and also to the other two placed on the orthogonal planes. With 4 difficulty levels and 4 initial values distributions, you can customize your game and have every time a new exciting challenge to solve.
Real Mah Jongg is a social game that originated in China thousands of years ago. Four players, named after the four winds, take tiles from a wall in turn. The best tiles are made of ivory and wood; they click pleasantly when you knock them together. Computer Solitaire Mah Jongg (xmahjongg being one of the sillier examples) is nothing like that but it's fun, or it must be, since there are like 300 shareware versions available for Windows. This one is for X11 and it's free.