The Rubicon Pass RPG is running version 2.4 of RPGD, which is a port of the classic TProBBS package from the Apple II. RPGD is less of a BBS and more of a primitive multiplayer RPG, but it was great fun back in the day. I was introduced to it when I first logged into Apocalyptic City, the only BBS in the area to run it. Talk about nostalgia...
In order to connect, you'll need to telnet to port 6700 of rubicon.optera.net, and your client will need to properly support ANSI graphics, and a couple of other things.
On most Unix systems, you can use a ~/.telnetrc file like so: