8BitMUSH - A social MUSH with BBS-like text art, an expansive MUSHcoding tutorial, many puzzles, playable arcade games, and a stock market and mini-capitalism system.

After Five - A virtual community which encourages diverse people all over the world to meet for discussions on different technical and personal topics.

AuroraMUSH - A small, friendly social MUSH.

ChaoticMUX - Social MUX where one can hang out and make friends. A bit of warning though: people there may seem a little crazy at first, but new-comers get used to it.

Discordia MUSH - DiscordiaMUSH is a relaxed social place to be.

DynamixMUSH - Explorable areas and multiplayer attractions. Includes a space adventure, an ocean rpg, and a variety of player run areas. Free building is encouraged.

404 M*U*S*H - A place to hang out. Includes the MUSH 101 schoolhouse for new MUSHers. The latest versions of PennMUSH are beta-tested here.

MUSHMellow - A Pueblo-enhanced world that includes areas based on Mayberry, the old west, the Andes and Norse myth.

MyrkaMUX - MyrkaMUX is a social MUX with no particular theme and where building is encouraged.

PogoMUSH - A social MUSH with a theme based around Walt Kelly's Pogo comic strip.
Meta Description: [ We here at PogoMUSH pride ourselves in our nonsensical philosophical debates about toilet paper, etc.. We are some fun loving people who range from lovers of classical to lovers of techno. But remember The KLF is gonna rock you! Pogo is a social MUSH which pulls its theme from all over. We ha... ]

Pouting Pixie MUSH - This RP/Social MUSH focuses on community and offers players the ability to roleplay in any of the existing worlds or just socialize.
Meta Description: [ This is a RP/Social MUSH created by a handful of individuals who have had several years of experience in the online community to incorporate all the positive aspects that a virtual society can deliver. Our playerbase is small but friendly, and we boast a diverse population with players from diff... ]

Shambala MUSH - Log in, meet and chat with people from all over the world, play games, and just generally relax and have a good time. Interaction takes place in a friendly world with parks, shops, dance clubs, and many other virtual places.
Meta Description: [ Shambala is a social MUSH (Multi-User Shared Hallucination; that is, a virtual world) where you can log in, meet and chat with people from all over the world, play games, and just generally relax and have a good time. Your interaction takes place in a friendly world with parks, shops, dance club... ]

TinyTIM - The world's oldest MUSH. TinyTIM has hundreds of areas to explore.