telnet://genocide.shsu.edu:2222
Genocide is a LPMUD (a Multi-User Dungeon)
at Sam Houston State University in Huntsville, Texas.
It was one of the first (the first?) player-killing mud,
that is, a MUD whose goal is to kill other players
rather than computer-generated monsters.
Genocide has been running since January, 1992.
There's also a webpage at:
http://www.shsu.edu/~genlpc