Earlier quoted context omitted.
I had the same question as we do mostly PHP; I'm guessing it just uses Ruby as the host software. I installed the Gem and was able to acquire a URL but kept getting an error: An error has occurred: {"stack":"Error: socket hang up\n at Socket. (http.js:1271:45)\n at Socket.emit (events.js:64:17)\n at Array.0 (net.js:825:12)\n at EventEmitter._tickCallback (node.js:126:26)","message":"socket hang up"}
You need to have some server listening on your local machine at whatever port you are creating the tunnel for. If you just wanted to test it out you could start something like "python -m SimpleHTTPServer" and then "show 8000", which will serve files from your local machine at your showoff url (I might recommend running the server in an empty directory).
Sheesh. Ruby runs over 3000, if you're not running the ruby server on 3000 there's not going to be anything listening.
Facepalm.