Arianne is an engine to develop multiplayer online games like Stendhal
JamochaMUD is a Java MUD/MUCK client.
Provides a full suite of clients and servers for virtual worlds.
Fast paced action RPG with retro graphics style
A simple telnet (and possibly SSH) server
3d peer to peer chatroom where associated pairs of text gravitate
A simple command line tool that operates on Tibia automap files.
Free MMORPG Engine. Develop and host graphical browser-based games.