xtee (cross-tee/expanded tee) is a program for building complex pipelines. It resembles the tee command, except that instead of copying stdin to stdout, it copies an input file to stdout and stdin to an output file. You can use xtee for building things like a bidirectional HTTP filter (using netcat and sed).
xtell allows you to send messages between computers running xtell server. It is easy to use in scripts (i.e. to notify you when you get a mail or something else happens) or as a network-aware replacement for write(1). It was originally based on Michael Bacarella's ident2 server and Jozef Knepp's VMS implementation.
The xterm program is the standard terminal emulator for the X Window System. It provides DEC VT102/VT220 and Tektronix 4014 compatible terminals for programs that can't use the window system directly. If the underlying operating system supports terminal resizing capabilities (for example, the SIGWINCH signal in systems derived from 4.3bsd), xterm will use the facilities to notify programs running in the window whenever it is resized.
xtermcontrol enables dynamic control of XFree86 xterm properties. It makes it easy to change colors, titles, fonts, and the geometry of a running xterm, as well as to report the current settings of the properties. Window manipulations such as (de)iconify, raise and lower, maximize and restore, and reset are also supported. It also lets advanced users issue any xterm control sequence.
xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the X Window System. It includes lower case, the real time clock, hi-res graphics, serial port, parallel printer, mouse, cassette, sound and music output (requires OSS), 5" and 8" floppy disk drives, and even hard disk drives. The emulated floppy and hard disk file formats are compatible with the popular MSDOS-based emulators by Jeff Vavasour, Matthew Reed, and David Keil. Under Linux, physical floppy disk drives are also supported. Physical cassettes can even be read and written.
xtweet360 is a small Perl script to publish your Xbox status to Twitter automatically. The main reason for this is to avoid signing up to yet another Web service and giving them your password for Twitter. xtweet360 publishes your full playing status, including the level you're on if you choose, and has a link to your gamer profile. It's a Twitter authorized app, so it will say posted by xtweet360.