Equus is a game I wrote quite a long time ago. At the most basic level, is a simple variation of Tic-Tac-Toe that is played on a 5x5 grid instead of 3x3. The object of the game is to get 5-in-a-row. However, there is a catch: you and your opponent may "rotate" rows and columns of pieces up, down, left, and right to foil your opponent and bring yourself closer to victory.
If you'd like to try it, it works great in DOSBox, which is availble for Windows, OS X, Linux, and a bunch of other systems.
Atraxx is another game I wrote around the same time I wrote Equus. It was a straight clone of Ataxx. However, the code, the graphics, and every compiled copy has been completely lost. The only thing that remains are those two screenshots. Bummer.
MiniHaven is a UNIX-based chat server that originally was written to be an entry in an obfuscation contest, of all things. The contest was to write a fully functioning haven-type chat server in less than 50 lines of C code. My entry did not win the contest, but it grew and grew into one of the more powerful and definately the most configurable haven chat servers ever built. Over the years, the software has gotten somewhat of a loyal following, so I continue to offer the software to anyone who wishes to download it.
HC (Hotel California) is another UNIX-based chat server that I wrote. It is actually much bigger and a lot more powerful than MiniHaven, but is also a lot more complex and less user-friendly. However, chat servers based off of Hotel California have been running continuously for well over 15 years. In 1995, at the height of its popularity, the Hotel California chat cluster (HC has the ability to link to other HC servers) served 11,000 unique users and fielded 18 million connections. If you'd like to try HC for yourself, you can give it a shot by downloading it.