xcplay is an ncurses interface to XMMS. The UI is a clone of cplay, but using XMMS as a backend instead of console players, running either as a GUI-stripped daemon or on a virtual X server (Xvfb). Advantages over cplay include seeking for many more formats, detachment, unlimited instances, and console player independence.
xcw is a small utility that makes it possible to input text into any X11 program with a Morse key. It reads Morse from a straight or iambic key connected to a serial port, decodes it, then sends the decoded text to the X window currently in focus. The Morse code sound is played through the sound card.
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.