trf is an extension library to the script language tcl, as created by John Ousterhout. It extends the language at the C-level with so-called "transformer"-procedures. With the help of some patches to the core the package is able to intercept all read/write operations on designated channels, thus giving it the ability to transform the buffer contents as desired. Existing transforms include Base64, UUencode, Hashes (SHA, MD5, ...), error correction codec, zlib-based compression, script level transforms.
Common C++ is a highly portable C++ class library meant primarily for the development of portable threaded applications. Support is provided both for POSIX platforms and native builds under Win32. The goal is to provide a truly common C++ framework for writing portable threaded applications that do not require a huge amount of runtime overhead to support, and hence can make C++ and threads suitable even for the development of trivial servers and applications.
wxPython is a Python extension module that wraps the wxWidgets cross-platform GUI library and provides an alternative to Tkinter and PythonWin. It attempts to mirror the class hierarchy of wxWidgets as closely as possible and is very versatile. It can be used to create standalone GUI applications or can be used in situations in which Python is embedded in a wxWidgets C++ application as an internal scripting or macro language. The currently supported GUIs are Win32, GTK/X-Windows, and Mac OS X.
distributed.net is a loosely knit group of computer users from all of the world that is taking up challenges requiring lots of computing power (most notably the RC5, DES, and OGR cracking contests). It is simple to participate in the challenges by downloading and running their client software (which uses idle CPU time to complete its tasks).
Spin Chat is a completely Java based Chat application, both server and client. It has been originally developed on Linux and runs excellent on it. It features vast customization possibilities, multi-channels, built-in spam control, graphical administration tools, I18N, channel logging, ignoring, emotes, etc.
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.