What is a MUSH?
In the simplest of terms, a MUSH is a game. However, it is a game in which multiple users can connect and interact in real time. 'MUSH' is often mentioned as meaning Multi User Shared Hallucination.
The MUSH server acts as a host to which many players can connect via telnet or a client program to the game. There are numerous client programs available across almost every platform.
A MUSH is comprised of two main components:
A Player is a Character created by you, the user. Characters are uniquely named objects which can connect to the game via a client or telnet (see below for client recommendations). These characters are often similiar to a character you would play in an RPG. They can have descriptions, possessions, movitivations and anything else you can picture an RPG character having.
A Room is a chunk of the game world. It can be a tavern, a road, a mountain top, a dungeon or any other physical space. Rooms are the main areas in which Players and Things exist. These rooms have descriptions which convey what the room is and how it appears.
MUSHes often vary in terms of what they are. Many MUSHes are games centered around a theme based on popular fiction or Role Playing Games. Others are used mostly for socialization or chat between players. The game administrators, or wizards, define what the game will be as they create it.
What is a MUD?
A MUD (Multi-User Dungeon or Multi-User Domain) is a more "general" class to which MUSHes belong. However, those that are called MUDs and MUSHes are quite a bit different in most cases. MUDs are generally less focused on storytelling and interacting and more on programmed encounters, fighting and automated challenges. In many ways it's like a text-based MMORPG. Despite the fact that they are often run privately, however, many are even more engaging than large commercial ventures. Nevertheless, Multiverse Crisis is NOT a MUD in any real way other than simply being a MUSH, which is part of the MUD "family" of text-based games.
What are some MUSH clients?
If you're feeling masochistic, you can use Telnet, which comes default with recent versions of Windows (including Windows XP, Windows 2000, Windows Me and Windows Vista). It should also be nearly universal on Unix-based systems, including Mac OS X.
The old standby for Unix systems is TinyFugue. It's command-line based. Although the interface is a bit convoluted it's also got a lot of powerful scripting abilities you won't find in most MUSH clients. If you're using Linux, your distribution might have a pre-built binary package, which may or may not fill your needs (if you're new to MUSHing it almost certainly will). There are also a variety of graphical clients for Unix/Linux of varying quality. Further, one might have luck running a Windows-based client under Wine.
MUSHClient is often recommended for Windows.
SimpleMU is another recommended for Windows.
JamochaMUD is a client written in Java, so it can (in theory) be used on any platform - even within a browser. We have an automated connection using JamochaMUD for Multiverse Crisis here, which means that if your browser supports Java you can connect from inside it. Instructions on how to use this automatic connection are available here.
Potato MUSH Client works reasonably well, and is available for Linux and Windows (and possibly other Unix-based systems). At least one user has reported reasonable success with the Linux port. A MacOS X port is also planned at the time of this writing.
Atlantis is a client for Mac OS X, which the person writing this particular entry cannot vouch for being either good or bad.
Savitar is another client that Mac OS X users may want to try - again, this person cannot vouch for it being either good or bad.
The MacOS MUD Zone also has other clients (which is where the other Mac clients on this list were obtained), though some of them seem to be a bit old, to say the least. Some of the clients it lists seem to be usable on pre-OS X machines, even though there probably aren't many people reading this page that use one very often. It also lists telnet clients for the Mac. Some listings point to dead links, so you may want to try The Internet Wayback Machine if you're desperate to try a particular client.
There are, however, many MUSH clients. Those who don't like or can't use the ones listed here, including Mac users, are encouraged to look through Wikipedia's listing of MUD clients (most of which are compatable with MUSHes) at http://en.wikipedia.org/wiki/MUD_client_support_table.
As a final resort, there are a few telnet and SSH clients you can use. This is generally not recommended unless you know what you are doing. Probably the best one available today is PuTTY, which is for Windows, and also has a Linux port, and is typically used for directly connecting with things like Unix systems from afar. It can work for a MUSH, but you may get your input a bit mixed up with your output.
Please note - we ARE NOT technical support for any MUSH client, although if you ask nicely players who have the client may be able to help you if you're experiencing difficulties.