Lame MUD
A lame multi-user dungeon engine.
Lame MUD is planned to be an engine for virtual text based worlds (as opposed to the seizure inducing modern ARPG/MMORPG titles).
Currently, it's still in pre-alpha. The sources available for download are not even remotely resembling anything like a MUD. There is a network layer established and the server acts as a one room chat server.