- Dungeons and Dragons is designed by Gary Gygax and Dave Arneson and published by Tactical Studies Rules, Inc.
- Will Crowther writes Colossal Cave Adventure in Fortran for BBN's PDP-10.
- Inspired by Adventure a group of students at MIT write a game called Zork for the PDP-10 which became popular on the ARPANET.
- Zork is ported under the name Dungeon to FORTRAN by Crazy Bob, a programmer working at DEC in 1978.
- Roy Trubshaw, a student at Essex University in the UK, starts working on a multi-user adventure game in the MACRO-10 assembly language for a DEC PDP-10. He names the game MUD (Multi-User Dungeon), in tribute to the Dungeon variant of Zork, which he had greatly enjoyed playing.
- Tom Truscott and Jim Ellis of Duke University create Usenet.
- The final version of MUD1, completed by Richard Bartle, becomes more widely accessible when a guest account is set up that allows users on JANET (a British academic computer network) to connect between the hours of 2 am and 8 am and at weekends.
- MUD1 is closed down leaving MIST as the only remaining MUD running on the Essex University network, becoming one of the first of its kind to attain broad popularity. MIST ran until the machine that hosted it, a PDP-10, was superseded in early 1991.
- AberMUD is written in B by Alan Cox at University of Wales, Aberystwyth for an old Honeywell mainframe.
- Richard Skrenta writes Monster in VMS Pascal for the VAX and publicly releases it in November 1988.
- In January 1989 Michael Lawrie sents a licenced copy of AberMUD3 to Vijay Subramaniam and Bill Wisner, both American Essex MIST players. Bill Wisner subsequently spreads AberMUD around the world.
- James Aspnes creates a stripped down version of Monster which he calls TinyMUD, and publishes it late 1989.
- Lars Pensjö writes LPMud wanting to create a world with the flexibility of TinyMUD and the power of AberMUD.
- Inspired by AberMUD, Sebastian Hammer, Tom Madsen, Katja Nyboe, Michael Seifert, and Hans Henrik Staerfeldt release DikuMUD, leading to a virtual explosion of hack-n-slash MUDs based upon its code.
- Merc is created by Michael Chastain, Michael Quan, and Mitchell Tse at the University of California, Berkeley and first released on 18 December 1992.
- Mudpedia is launched.