Isengard is also the name given to a popular free telnet MUD based on the Mordor code base. The game world is loosely based around the books of J.R.R. Tolkien and can be found at port 4040. To play it well you will need a MUD client such as GMUD or ZMUD. Be warned though, I’ve found it utterly addictive and you can easily lose days of your life playing it.