Momoko is a generic, object-oriented, modular, extensible environment for creating multi-user environments. It is suitable for writing MUDs, servers, and community-based Web sites. It is written in pure Java and supports Java and Python as internal scripting languages. Momoko provides facilities for organizing objects into tree-based hierarchies, orthogonal persistence, a transparent distributed objects system, remote access to source code and user files via WebDAV, a telnet-enabled shell for manipulating the object database, and an integrated build process which can be triggered remotely.
NFMCA is a MUD client with basic features in the form of a Java applet. The GUI is written with Swing, so one needs Java Runtime Environment to run it. Besides running in a browser as an applet, it also supports standalone mode. Features include dealing with a limited set of ANSI codes (foreground colors and underline), multiple languages (as you could expect from a Swing program) and font changing (two features which are absent in some much more complicated clients), smart scrolling, command history, detachment ability for applet mode, handy selection/copying mode, and more. It supports English as the default, and Russian for Russian-localized operating systems. NFMCA should run on any platform (tested on Windows and GNU/Linux).
XMud is an extensible MUD, inspired by LambdaMOO and LPMUD. It allows users to extend the system at run-time by creating new objects. Objects are Java classes that follow certain rules with respect to manipulating the state. It was designed with with scalability in mind; the system may be composed of N servers and M clients. Each server is nothing more that a state manager that controls reading, writing, and locking state elements. Methods are executed at the client level and generate state change requests that are sent to the server.
SMM++ Mud Client is a mud client with extended and unique features. Aside from all standard mud client functionality like ANSI color support, aliases, action triggers, and tab-completion, SMM++ features a highly-customizable user interface (labels, buttons, and menus) and unique and powerful mapping capabilities, and SMM++ is the only mapping crossplatform (Tcl/Tk based) mud client available.