This is a resurrection of Matthias Blume's VSCM Scheme implementation.
Kawa is a full Scheme implementation. It implements almost all of R5RS (for exceptions see Restrictions), plus some extensions.
Eleven is a programming language for creating robust, scalable web applications. It offers a 20x programmer productivity increase over ASP, JSP, etc. by automating state management and UI layout. The compiler generates ready-to-run PHP or mod_perl code.
Here we have fun developing software related to embedded extension languages and small languages in many application domains, using existing languages and/or creating new ones.
The MDK provides a simulator of D. Knuth's MIX computer, and a development environment to write, run and debug MIXAL programs on it.
An optimising compiler for the R5RS Scheme language, written in R5RS Scheme, compiling to ANSI C, supporting Unix-like platforms, performing whole-program analysis and online partial evaluation.
OxyScheme is a compiler for a programming language Scheme intended for use on .NET framework
PLT Spy is a Python to Scheme translator.
Redtail is a scripting engine library and script language. The Redtail library provides the ability to execute Scheme-like Redtail scripts from within an application, increasing flexibility.
STklos is an efficient Scheme System providing a powerful Object System
An R6RS Scheme implementation
Vicare Scheme is an R6RS compliant fork of Ikarus Scheme, aiming to become a native compiler for R6 Scheme producing single threaded programs running on Intel x86 32-bit and 64-bit processors; it is tested only on GNU+Linux, no official support for other platforms is present. Vicare offers arbitrary precision integers through GMP. It implements an optionally included foreign-functions interface based on Libffi. Ikarus Scheme is an almost R6RS compliant implementation of the Scheme programming language; it is the creation of Abdulaziz Ghuloum, which retired from development in 2010.