BHL is an Emacs mode which enables you to convert plain text files into HTML, LaTeX, Texinfo, SGML (Linuxdoc), and TXT files. The BHL mode handles three levels of sections, many sectioning styles, common font-styles, any kind of lists, tables, URLs, horizontal rules, and Wiki names. BHL handles a list of links (lol) and a table of contents (toc): you can browse the lol and the toc, insert them where you want, and update the sections' numbers with one keystroke.
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.
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.
ECB is a source code browser for (x)emacs. It displays a couple of windows that can be used to browse directories, files, and file contents like methods and variables. It supports source code parsing for languages like Java, C, C++, Elisp, Scheme, Perl, TeX, LaTeX, etc. In addition, it offers an (optional) permanent "compile window" at the bottom of the emacs frame, which is used to display all help and compile output. The rest of the frame is called the "edit area", which can be divided into several edit windows that are used for editing the sources. Deleting some of the edit windows neither destroys the compile window nor the browsing windows. It requires the CEDET suite.
Easymacs is an easy-to-learn, one-size-fits-all configuration for new users of GNU Emacs. It sets up key bindings that conform to a common denominator of the Gnome/KDE/OS X/Microsoft Windows human interface guidelines, and provides function-key bindings for other powerful Emacs features. It is fully documented, and the new user can productively edit text right away, without going through the Emacs tutorial. Many commonly-used functions can be accessed without having to learn the "chords" or multiple keystrokes that Emacs uses by default.
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.