LiveSystems MyMUD 2.0:

MyMUD is a full fledged multiuser adventure game suitable for disksharing
networks like Novell and Lantastic.  MyMUD implements filelocking and
doesn't need a dedicated machine.  Standalone use is simple.  MyMUD comes
with a number of worlds, full source and is copyrighted freeware.  Use it,
play with it, change it etc. The game looks like TinyMUD and should appear
familiar to who ever played the game.

Enjoy!