“MUSH” stands for “Multi-User Shared Hallucination.”

Really, it’s just a silly shorthand for a type of MUD (Multi-User Dimension) that uses a specific codebase, called PennMUSH (or TinyMUSH or TinyMUX or…you get the idea), to create a special text-based platform, accessible online around-the-clock, for purposes of roleplaying.

Some simple comparisons to help give a better sense of what a MUSH is:

• It’s like Skype, but with a grid of rooms instead of just the chat interface. Each room serves as a stage, a roleplaying space, for the players within it.
• It’s like play-by-post, play-by-email, or play-by-blog, except that everything happens in real-time.
• It’s like tabletop gaming, with a virtual table, virtual dice, and the players and DMs come from all over the world. We’ve also got to supply our own snacks.
• It’s like Live-Action Roleplaying (LARPing), without the travel expenses, the uncomfortable living conditions, the bruises, the mosquitoes, or the inclement weather.
• It’s like a shared-world novel, evolving and changing because of your participation as one of the story’s authors.
• It’s like improvisational theater, where you run with a set of circumstances and turn it into an entertaining scene for yourself and others.