Artha is a handy thesaurus based on WordNet with distinct features like global hot key look up, passive desktop notification, regular expression based search, etc. Artha may be used as a free open-source replacement/clone to the proprietary WordWeb Pro thesaurus (which is also based on WordNet) on Unix-like and Windows operating systems.
audiopreview is a command-line tool that plays previews of many audio file types (Ogg, MP3, etc.), video file types (AVI, MPEG, Real, etc.), and Internet streams. It can also be used as a regular command-line media file player (i.e. play the files entirely like yauap or mpc123 would).
Conky Images Display is a program that displays the cover of the song currently playing. At the moment Rhythmbox, Amarok 1.4 and 2, and exaile are supported, but support for others is planned. It can also download missing covers. CID is fully configurable thanks to a simple configuration panel.
DeTraS provides several tools to track development activities by registering applications that developers use on an X11 session. It also allows you to send collected data to a server and takes care about your privacy. The idea behind DeTraS is taken from Timeline, a shell script written by Nat Friedman.
Reindeer is a C library for the rendering of virtual scenes, mainly in three dimensions. The library dynamically loads backend modules to do the rendering. Currently there is only a backend for OpenGL, but ideas for future backends are a raytracer and perhaps Direct3D. Any number of rendering contexts can live at the same time. Contexts are tied to a backend, and backends are automatically loaded and unloaded on demand. Resources are defined globally and can be used by any number of contexts at the same time, even in different backends. The main goal is to make it easier for developers to write applications that have many rendering contexts with shared resources and automatic state management. Another advantage is that the user can choose in which way a scene should be rendered without recompiling the application. For example, a scene could be rendered with a rasterizer like OpenGL at one point, and with a raytracer at another. Reindeer can also be used to get portable graphics output. Reindeer is not a scene-graph library or a game engine, but it can be used to implement them. It's still up to the application to create and manage the native contexts that the Reindeer backends can work on. For example, an application would still need to use GLX or equivalent to be able to use the OpenGL backend. The Reindeer project also provides a package called GTK-Reindeer that makes this easier for developers of GTK+ applications.