DMDScript
   Implementation of ECMA 262 scripting language; standalone and ActiveScript versions available. By Digital Mars.
   http://www.digitalmars.com/dscript/

JSLibs
   Standalone JavaScript development environment; goal: turn JavaScript into a general-purpose scripting language. Has set of native modules that contain many general-purpose classes and functions. Open source, GPL.
   http://code.google.com/p/jslibs/

Rhino - JavaScript for Java
   An open-source implementation of JavaScript written entirely in Java.
   http://www.mozilla.org/rhino/

SEE: Simple ECMAScript Engine
   A small C library that provides a JavaScript parser and runtime environment, conforming to ECMAScript Edition 3 and JavaScript 1.5, and with compatibility modes for JScript et al. [Open source, BSD-style licence]
   http://www.adaptive-enterprises.com.au/~d/software/see/

Sun Labs Lively Kernel
   Web programming environment, by Sun's Project Flair. Goal: give web programming equal simplicity, generality, flexibility as used in desktop programming for 30 years, but without installation, upgrade issues of desktop programs. FAQ, forums, interactive t
   http://research.sun.com/projects/lively/

deployZone
   Cross-platform e-mail, database and web server, supports Server-side JavaScript to build Internet applications in an object-oriented, web-based content management system.
   http://www.deployzone.com/