GLAME (GNU/Linux Audio Mechanics) is meant to be the GIMP of audio processing. It is designed to be a powerful, fast, stable, and easily extensible sound editor for Linux and compatible systems. It has full support for non-destructive editing including undo/redo and applying LADSPA effects. Its supported platforms are Linux, BSD, IRIX, and OS X. It uses guile and libxml, and the GNOME libs available is highly recommended. MP3 and Ogg files can be processed if libmad and libvorbisfile are installed.
gnokii is a multisystem tool suite for mobile phones. It provides a library to communicate with a phone hiding the communication protocol. The library handles SMS, phonebook, calendar, phone calls, and other mobile phone capabilities. It supports Nokia-FBUS mobiles, AT-capable phones (most of the mobiles), as well as Symbian-based phones.
Cfengine is a tool for setting up and maintaining BSD and System-5-like operating system optionally attached to a TCP/IP network. You can think of cfengine as a very high level language, much higher level than Perl or shell: a single statement can result in many hundreds of operations being performed on multiple hosts. Cfengine is good at performing a lot of common system administration tasks, and allows you to build on its strengths with your own scripts.
gPS (graphical Process Statistics) is a system information applet based on GTK+. It displays the processes of one or more computers (like ps or top), allows killing, renicing, and signal sending, shows lots of details on selected processes, shows CPU/Memory usage and history graphs, and is capable of watching networked computers in addition to the local one. It also provides an easy way to send signals to processes based on their owners (uid), groups (gid), and string matching.
gRio500 is a Gnome/GTK program that lets you interface with the Rio500 MP3 player by Diamond/S3/SonicBlue. You can currently create/delete folders, add/delete songs, format memory, rename folders/songs, automatically downmix/resample MP3s during transfer, and preview MP3s (play/stop controls). You can interface with both internal and external memory (Smartmedia).