ClassyTcl is a dynamically loadable object system for Tcl. Both a Tcl-only and a C implementation are available. It also doesn't require patches to the Tcl core, which makes installation and maintenence easier. Performance is quite adequate. The C version is gives extra speed, and makes it possible to implement some methods in C. In contrast to other object systems for Tcl, it is not modeled after the object system designed for a completely different language, such as C. The system is simple but flexible. Classes and objects are dynamic, and can easily be queried, changed, and debugged at runtime.
clo++ is a command line option parser generator. Given an XML file that contains a description of your program and its options, clo++ can generate code to parse its command line. In addition to code generation, clo++ can also generate man pages. Other languages and output formats can easily be added because clo++ generates its output using templates.
CMUbik is a library for mantaining a syncronized Berkeley database over multiple hosts. It has good failure semantics and strong authentication provided by the Cyrus SASL library. Its API is very similar to that of Berkeley DB, allowing existing applications to use it very easily.
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.
CTWM is a highly-configurable window manager based on the classic TWM window manager. It supports xpms, multiple workspaces, advanced icon managment, animated icons and backgrounds, 3D titles and borders, etc. It offers rudimentary Gnome support and is backwards-compatible with TWM.
CUP is an pure Java LALR Parser generator that generates Java source code. It serves the same role as the widely used program YACC , and includes most of YACC's features. CUP supports embedded Java code, produces java-based parsers, and comes with sample grammars for Java 1.0, 1.1 and 1.2.
CVSsuck is a mirroring tool for CVS repositories. Unlike other tools such as CVSup or rsync, it uses cvs command to access the repository. So, it works well with remote repositories without a special server or shell account. However, it is inefficient because the CVS client/server protocol is not designed for mirroring.