The VROnline project is universal 3D virtual reality engine for games with client/server architecture, free 3D camera, user configurable actions and AI scripts. It's based on C# and directX (now 9.0) technology. It can manage many data models(rpg,sims).
A graphical isometric multiplayer virtual reality server in MUD-style. Rooms and server code can be changed online. At the moment, there is also an IRC link. Clients are available in Java and Python/C.