I did this for a website once, but I just ran it on port 23 (telnet). The "game" version had all the same information and functionality as the more mainstream-designed www site on the same host. It ran for 4 years though and not once was it found or used by a real human as far as I can tell. Made me feel like the internet was really dead. I first discovered MUDs as a child while portscanning for open SMTP servers so I could send spoofed email to my friends. It really did used to be a different experience using the net.