Cooledit is a text editor for the X Window System. It contains a built-in Python interpreter for macro programming, and it includes a rich set of utilities and features. It has multiple edit windows and a beautiful, intuitive user interface that requires no tutoring to learn to use. It can be used as a programmer's IDE and has syntax highlighting for a large number of programming languages. It contains an interactive graphical debugger for C/C++ programs.
Cook is a tool for constructing files. It is given a set of files to create, and recipes of how to create them. In any non-trivial program there will be prerequisites to performing the actions necessary to creating any file, such as include files. Cook provides a mechanism to define these. When a program is being developed or maintained, the programmer will typically change one file of several which comprise the program. Cook examines the last-modified times of the files to see when the prerequisites of a file have changed, implying that the file needs to be recreated as it is logically out of date.
ControlFreak is a scriptable toolbar application. You write scripts describing the layout and what you want the toolbars to do, and ControlFreak creates the toolbars. The toolbar components run shell commands when activated, and you can also use the state of various toolbar components (ie the contents of a text box or whether a toggle button is up or down) to influence what shell commands are run and what arguments they use.
ConTemplate is a set of mode-based templates for Emacs, with intelligent prompting for variable fields, multiple text formatting options, and an easy mechanism to define new templates which automatically sets key-bindings and menu entries. Currently supported modes include C, Emacs-Lisp, Debian package, and Mail (for form letters).
console othello is an Othello-style board game running on a text console. The AI is not brilliant and the game is simple, but several improvements are planned, including support for a web version and network play. The source should (theoretically) compile on any platform supporting printf() and fgets(): Linux, Solaris, Windows, BeOS, etc.
Conserver provides remote access to serial port consoles and logs all data to a central host. Local and network serial connections are supported. Server console history can be replayed from the console app even if the server is down, and multiple users can connect to a single serial connection.
Cons is a Perl-based software construction tool (i.e., substitute for make). It offers a number of features not found in make or other build tools, including integrated dependency analysis (no more "make depend" to generate static lists of .h files), complete dependency analysis across multiple directories, multiple side-by-side variant builds, compilation from code repositories, MD5 signatures instead of time stamps for determining whether a file is up-to-date, and extensibility via Perl.