GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
gogetty is a tiny getty written from scratch. It'll only work with linux VCs and possibly other software terminals, as it doesn't try to perform any terminal ioctls (for example, to set baud rate). However, it is the only extant getty to correctly handle session and program group IDs, letting you use it to start an arbitrary program on another console.
Gsh is a graphical shell. It integrates a terminal window, a normal shell, and various GUI components into a single package which allows easier and more powerful operations than you can have with a shell and terminal window seperately. Gsh is already fully functional, but there are many avenues of devlopment yet to be explored.
The Linux Serial Sniffer allows you to sniff serial data up to 460Kbs via a Comtrol RocketPort or to 115Kbs using the standard ttyS0 and ttyS1 ports. Sniffed output can be captured to disk or displayed directly on screen. A user filter is included to assist specific customisation. The Linux Serial Sniffer can selectively operate in either a "ghost mode" where there is no data flow time impediments, or via a "capture and forward mode", where the user can flexibily intercept and extend the data stream to suit from either direction.
mcl is a MUD client running in a Virtual Console under Linux or using standard TTY routines under any other UNIX. Embedded Perl or Python offer very high tweakability. Other features include huge scrollback, a stable input line with the MUD prompt, Perl regexps for actions and substitutions.
The mgetty package contains an intelligent getty for allowing logins over a serial line (such as through a modem) and receiving incoming faxes. The companion program sendfax is used for sending faxes from the commandline or from other applications. The third main component is vgetty/vm which can be used with a voice-capable modem to implement an answering machine, a voice menu system, and similar things.