Larceny is a simple and efficient implementation of the Scheme programming language. Created originally as a test vehicle for research on garbage collection and compiler optimizations, Larceny has grown into a major multi-platform system, and is one of the very few implementations that support all four de facto standards for Scheme: IEEE/ANSI, R5RS, ERR5RS, and the R6RS. Development of Larceny has been supported by NSF, Sun Microsystems, and Microsoft.
Halyard is a scriptable multimedia engine with support for video, audio, graphics, and user interaction. It currently runs on Windows, and has a preliminary Macintosh port. It is based on PLT Scheme, wxWidgets, and the Quake 2 Engine. It includes a rudimentary IDE based on Scintilla.
Sepp is a version of the classic sliding puzzle game in which the properly ordered tiles form a picture. The picture is user-selectable, as is the tile-grid geometry. Additionally, Sepp implements an innovative kind of player aggravation: based on a user-configurable degree of evil, it decides, during each animation frame, whether it will disturb a tile while the game is in progress. Sepp is written for the DrScheme enviroment, which is available for all major platforms.
MzVim is the Vim editor with an embedded MzScheme interpreter. MzScheme is a lightweight, embeddable, scripting-friendly PLT Scheme implementation. It provides full access to Vim commands and registers, and to VimL built-in variables and functions, so there is no need to execute Vim statements in string literal form. It also features OS-independent threads and an event-handling mechanism which allows Scheme to be used for autocommands, keyboard mappings, and menus.
Kipt (Kizome's ISA Piercing Tool) is an HTTP proxy server and proxying name server with the ability to forward requests to other HTTP proxies or to get the documents directly from hosts. It can go through MS ISA Server or MS Proxy doing NTLM authentication. If you're stuck behind a restrictive firewall or proxy with at least one port open for outgoing connections and you have access to a machine outside, you can have nearly full Internet access by using this proxy and the socksify program from dante.
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.