Free Misc. Compilers
A functional programming system based on Haskell 98, the de facto standard for non-strict functional programming languages. Hugs 98 provides an almost complete implementation of Haskell 98.
The GNU Eiffel Compiler
Euphoria is a simple, flexible, and easy-to-learn programming language. It lets you quickly and easily develop programs for DOS, Windows and Linux.
Ghostscript, Ghostview and GSview
An interpreter for the PostScript language and for PDF, and related software and documentation
CLISP is a portable ANSI Common Lisp implementation by Bruno Haible. Interpreter, compiler, debugger, CLOS, FFI, Unicode, sockets, CLX. UI in English, German, French, Spanish, Dutch and Russian.
(Just Another Language) for dos/windows or linux