DGD (Dworkin's Game Driver) is a Modern Mud Server for which I wrote a couple of extensions. They are outdated a bit but given time and the availability of a fully patched release of DGD I will update them again:
Once I programmed a lot in Asymetrix's Toolbook and created some nice libraries like OpenSock, a native wrapper for Winsock that allows Toolbook to emulate Winsock clients but also servers.
Because of the power of Toolbook it's also easy to create applications like web servers serving dynamically created WebPages or VRML models. See the following links:
OpenSock for Toolbook is a openscript that lets Toolbook function as a server (http, (t)ftp qotd ect) while interacting with the content of the ToolBook application.
It has a separate page with the changelog.
Furthermore I played a lot on Kobra-mud. This mud is based on Star Wars and is, due to it's size, attention for detail, humor and other players, great fun to play.
I've also collected some useful Zmud triggers for Kobra mud. See the following links: