Elvis is a clone of vi/ex, the standard UNIX editor. Elvis supports nearly all of the vi/ex commands, in both visual mode and ex mode. Elvis adds support for multiple files, multiple windows, a variety of display modes including "hex" and "html", on-line help, WYSIWYG printing, and other miscellaneous extensions.
NetPlug is an extensible multi-connections, multi-protocol, network client program, written in pure Tcl/Tk. Includes a complete Irc client plug in that you should love if you like IrcII 'classic' look & feel (plus customizable style/colors scheme, sound,... Now includes full DCC support (with GUI), ircII like aliases and improved scripting (Tcl!), keywords (your nick...) highlighting, and more
SteelBlue is an Open Source Web application server similar to Cold Fusion. It extends HTML with tags to execute SQL commands, perform type checking on user input, loop over sections of code, and manipulate data. In addition, it has a Perl-like scripting language that can be embedded directly into the HTML for complex data manipulation. SteelBlue runs as a CGI script on Linux, UNIX variants (via gcc 2.8), and Win32. It includes native support for most popular relational databases and the embedded scripting language is extensible though a C++ API. Included in the distribution are a book about programming SteelBlue, many examples, and a full bulletin board application.
XCircuit is a UNIX/X11 program for drawing publishable-quality electrical circuit schematic diagrams and related figures, and producing circuit netlists through schematic capture. XCircuit regards circuits as inherently hierarchical, and writes both hierarchical PostScript output and hierarchical SPICE netlists. Circuit components are saved in and retrieved from libraries which are fully editable. XCircuit does not separate artistic expression from circuit drawing; it maintains flexiblity in style without compromising the power of schematic capture.
Yabasic implements the most common and simple elements of the basic language. It comes with goto/gosub, with various loops, with user defined subroutines and libraries. Yabasic does monochrome line graphics and printing. Yabasic runs under Unix and Windows, it is small (around 200KB) and free.