xSiteable is a complete all-you-need package for creating sites that are fully relational, open source, fully templating-enabled, using only XML-based technologies to help you create complex sites on the fly. It packs such features as topic maps, notation for content, and the fast Sablotron xslt parser.
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.
xd3d is a simple scientific visualization tool designed to be easy to learn. It can plot 2D and 3D meshes, with shadowing, contour plots, vector fields, iso-contour (3D), as well as 3D surfaces z=f(x,y) defined by an algebraic expression or a cloud of points. It generates high-quality vector PostScript files for scientific publications and still or animated bitmap images. The distribution includes the graph plotter, xgraphic.