Here is a small sample of multi-user dimensions in cyberspace. I'm working
on one right now, whitelight, a cyberpunk circle mud. The mud isn't open yet
but here is a look at the help files, or at least what's
been done on them. You'll need a telnet client for the title links, best to
visit the homepages first.
AmberMUSH, you can log in as a guest, or create a character from the homepage.