Wikipedia
IfMUD
ifMUD is a MUD associated with the rec.arts.int-fiction newsgroup accessible via telnet or a MUD client. It is central to the interactive fiction community, frequented by many of the genre's best-known writers. Every year, the XYZZY Awards are hosted on ifMUD during an online ceremony.
ifMUD was founded in 1997 by Liza Daly. It is written in the Perl computer programming language making use of an extensive hack of the earlier PerlMUD, with many additional features.