Kingdom Wars is a client/server chess daemon designed to run on multiple operating platforms. Both the client and the server are stand alone. The network protocal is open, and custom clients are welcome to be developed.
ErisMUD is a MUD/MOO engine and server written in Python and SQLite and supports many features: it has rooms, chat, NPCs, items, player creation, ANSI colors, etc. Internal commands take care of the development and maintenance.