Phalanx is a chess playing engine with agresive playing style. It does not have its own graphical interface, but can be used with general chess interface Xboard (Winboard) by Timm Mann. There is also a commercial version that runs as a native Fritz module and thus can be used with the Fritz graphical interface.
Netrek is a 16-player two-dimensional graphical real-time battle simulation with a Star Trek theme. A game is divided into two teams of 8 players (or fewer), who dogfight each other and attempt to conquer each other's planets.
Autorip and autotag are a pair of shell-scripts which automate the ripping and encoding of CDs to MP3. They were written with the idea of disconnected operation in mind:
* CDs can be ripped to WAV files at anytime,
* CDs are identified from FreeDB the next time the machine is connected to the net,
* WAV files are tagged and encoded to MP3 at a later time.
As if the Linux world did not have enough CD players, I wrote one myself. I wrote the CD player by finally understanding how to use ioctl() and how to understand the information in the linux/cdrom.h file.