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.
GNU Go is free program that plays the ancient board game of Go. Its original concept is based on the article "Programming the Game of Go", Byte, Vol.6 No.4, by J. K. Millen. GNU Go has since evolved into a more sophisticated program. After thousands of games played on the No Name Go Server (NNGS), it is rated around the 8th kyu level.
GNU Make examines the timestamps on a set of interdependent files, and, if necessary, issues commands to bring them up-to-date. The user creates a makefile describing the files, their relationships, and the commands to run. Most often make is used to rebuild libraries and programs when their sources are changed, but it can be used for any situation where one set of files needs to be generated from another set.
GNU Phantom.Home is a computer controlled home automation system. The software includes a circuit diagram for building the Phantom.Home.Controller, a simple circuit board that attaches to your PC's parallel port. Using the combination of hardware/software you can control (i.e. flip on or off) nearly any 120V device. And with a little bit of electronics know-how, you can probably control nearly any device at any voltage by modifying the circuit board to meet your needs. The simple circuit included can be created and built for around $25. The modules cost around $10 (basically a heavy duty relay).
GNU Phantom.Security is a computer-controlled security system. Using the software and a simple circuit board (diagram included) that you build, you can create a good basic security system that is computer controlled. The system can use off-the-shelf security devices like motion sensors, door magnets, and fire/smoke detectors with little to moderate modification. You can have a total of 5 devices per port. And if the machine the system is running on is connected to a LAN/WAN or the Internet, you can have it send e-mail. If you have a pager or cell phone capable of receiving e-mail, then you will have around the clock intrusion/fire detection for your home or office.
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
GNU Wget is a utility for noninteractive download of files from the Web. It supports HTTP and FTP protocols, as well as retrieval through HTTP proxies. It can follow HTML links, download many pages, and convert the links for local viewing. It can also mirror FTP hierarchies or only those files that have changed. Wget has been designed for robustness over slow network connections; if a download fails due to a network problem, it will keep retrying until the whole file has been retrieved.