Reality is a client for Cyanide. Cyanide is intended to be the most dynamic multi-player online role-playing game ever made. This client uses an isometric perspective to present scenes. It is programmed with Python, pygame (SDL), and OpenGL. Full 3D movement is possible, and the server's code can be exchanged online.
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.
Mooix is a multiuser object-oriented dimension (a MOO) layered over top of your favorite Unix system. To the user, mooix looks much like any other MOO. To the programmer, mooix objects look like directories full of files: executable methods, properties, and links to other objects. MOOs have historically had poor support for such things as real programming languages, encrypted logins, multitasking, and editors. Mooix inherits all of these things from the Unix system it is based on. At the same time, it's not wedded too tightly to Unix (e.g., it implements its own permissions system that is much more suited to a MOO environment than the historical Unix system).
The Interreality project is a collection of Open Source, Free Software projects based on the Virtual Object System (VOS) platform. The goal is to develop a free and open platform for multi-user 3D virtual reality games, applications, and interactive, collaborative 3D virtual spaces. VOS is a powerful and generic network object framework designed to support a variety of high-performance applications. It is the basis for Ter'Angreal, a general-purpose browser application for entering and participating in 3D worlds.