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.
Bigloo is an implementation of the Scheme programming language. It relies on an optimizing compiler from Scheme to C. Bigloo enables connections between Scheme code and C code. It proposes many extensions to Scheme such as a regular parser compiler, an lalr parser compiler, pattern matching, an object layer, etc.
Roadsend PHP produces optimized stand alone applications, libraries, and Web applications from standard PHP source code. The compiler produces native machine code, not PHP byte code, so no interpreter is required. It is a new implementation of the PHP language and runtime environment compatible with Zend PHP. It does not share any code with the original PHP implementation.
Chicken is a Scheme compiler that translates most of R5RS Scheme into relatively portable C. It supports fully general tail-call recursion, first-class continuations, and has a very flexible and efficient interface to C and C++. Chicken implements several extensions to the Scheme language: lightweight threads, pattern matching macros, dynamic loading of compiled code, and various object-oriented paradigms, such as TinyCLOS, and others. The library system includes hundreds of convenient modules for practical use.
Thousand Parsec is a turn-based space empire building game, as well as a framework for creating a similar group of games, which are often called 4X games (eXplore, eXpand, eXploit, and eXterminate). Some examples of games from which Thousand Parsec draws ideas are Reach for the Stars, Stars!, VGA Planets, Master of Orion, and Galactic Civilizations. Unlike commercial alternatives, it is designed for long games supporting universes as large as your computer can handle. It allows a high degree of player customization, and features a flexible technology system where new technologies may be introduced mid-game.
STklos is a free Scheme System conforming to R5RS. The implementation is based on an ad-hoc Virtual Machine. It can also be compiled as a library, so that one can easily embed it in an application. Its features include an efficient and powerful object system based on CLOS, a simple-to-use module system, implementation of the full tower of numbers defined in R5RS, and easy connection to the GTK+ toolkit. STklos is the successor of STk, a Scheme interpreter tightly connected to the Tk toolkit.
jMax is a visual programming environment for building interactive real-time musical and multimedia applications by allowing the user to interactively design dataflow circuits. The basic data types that can go through are integers, symbols, lists, etc. It is an event-driven system and has been used for MIDI processing. A second part of the system (DSP) allows a continuous signal to flow through a circuit, which is most useful for PCM sound (ie. microphone, sound files, etc.). The system is extensible by using shared libraries, you may add data processor types, data types, GUI elements, device types, and more. Data processors may also be designed as circuits and reused.
Scsh is a systems-programming environment for POSIX systems and Win32, embedded in the Scheme programming language. It includes a high-level process notation for writing shell-script like programs, with pipelines and redirections. Scsh additionally provides low-level access to POSIX primitives, plus important non-POSIX extensions such as sockets. Scsh is implemented on top of Scheme48, a portable bytecode implementation of Scheme. A number of user-contributed extensions are available, including an extensible HTTP and FTP server, a socket-level PostgreSQL interface, a programmable text formatting language, and a Postscript generation language.
eINIT is an alternative init system. It's quite fast, since it can potentially be used without the help of any scripting at all, but it is still flexible and extremely modular. The focus is on speed and parallelisation, mostly with embedded devices and low-downtime servers in mind, and benchmarks do suggest that it's doing a fairly good job at that. It compiles cleanly (and should thus work, provided someone writes appropriate modules) on Linux, FreeBSD, and Darwin/Mac OS X.