x9wm is a clone or fork of the 9wm and w9wm X window managers. It is a light alternative for the Mac OS X desktop. All of its source code is contained in a single file. It supports an alterate red colored cursor. It is very light on resources, quite fast, very simple, and easy for long programming, editing, or Web work sessions. You can blend it with Nitrogen and Wbar to create a simple but elegant interface without iconic or stylistic clutter. It does not decorate windows with borders, and it is modal, controlled with the mouse.
xCover is a code coverage library for C and C++. It uses non-standard features available with GCC 4.3+ and Visual C++ 7.0+. Users place line-marks in each branch of each function or method in a component's source file, and the library is able to produce, upon request, a report of which of these has not been executed. Reporting can be done on a per-file, per-alias, or per-file-group basis.
xTests is a small, simple, lightweight, portable unit/component testing library for exercising C and C++ libraries. It relies on no platform-specific or compiler-specific constructs and doesn't require pre-processing of your source code by scripting languages or use macros to create secret classes that use Schwarz counters to register test cases. It relies on you to simply code what you want, and nothing that you don't want.
xbaydns provides a Web management interface for BIND 9. Its user-friendly Web interface is based on the Django framework. It has been tested on many OSes, including FreeBSD, Linux, and MacOS X Leopard. It provides an easy-to-use Web interface for DNS record management while implementing most of the advanced features provided by BIND.
xmbmon is a monitoring program for motherboards which can monitor the CPU temperatures and the frequency of CPU cooling fans, etc. The package includes "mbmon", which can be used at the commandline to report the temperatures, voltages, and RPM (rounds per minute) of the fans, and "xmbmon", which displays the three temperatures and a core voltage as simple curves.