MUSHes are text-based games, primarily used for role-playing or socialising. I’ve been MUSHing since late 2001, usually under the name Talvo or Mike. These days, the only place I regularly hang out is M*U*S*H, a social game which also serves as the flagship game for the PennMUSH server.
I’m also the author of Potato, a MUSH client for connecting to and playing MUSHes and other text-based games. I’ve also written a couple of simple web-based tools, for escaping text to include in MUSHcode, converting PennMUSH helpfiles into a format suitable for softcoded +help systems, and for unformatting MPP-encoded code so it can be uploaded to a MUSH.