Gnutran is a simple, Emacs-based front-end to a number of machine translation engines available on the Web. It can send emacs buffers to a translation engine, request a translation (e.g. English to Portuguese) and display the result on a new window. GNUTRAN interoperates with emacs-based email agents such as VM-Mail and features a highly configurable interface, allowing easy set up of new translation pairs through Emacs' customization interface.
The Kawa Scheme System is a full Scheme implementation, completely written in Java. Scheme functions and files are automatically compiled into Java byte-codes. Kawa does some optimizations, and the compiled code runs at a reasonable speed. It provides the usual read-eval-print loop, as well as batch modes. The Kawa compilation framework is also useful for implementing other languages on top of JVM. There is active development of XQuery (the XML query language), and less active development of Emacs Lisp, Common Lisp, and EcmaScript.
VM is a mail reader written in Emacs LISP for GNU Emacs and XEmacs. It can retrieve mail from local spool files or remotely via POP and IMAP, display and send MIME messages, thread messages, auto-sort messages into folders, and manipulate "virtual folders" of messages matching certain criteria. In Emacs versions with X support it provides an interface with toolbars, menus, and mouse-based message selection.
nethack-el is an Emacs major mode for playing nethack. Separate buffers are used for the map, status, messages, and menus. It features customization of keys and colors and user programmable hooks on game events. It supports GNU Emacs 20/21 and XEmacs 21, with graphical tiles on *Emacs 21.
ecasound.el is an interface to ecasound from within Emacs. It allows you to use an inferior ecasound process in an comint-derived mode. It features context-sensitive completion and wizards for adding chainoperators and the like. It allows you to write ECI-based applications in Elisp.