This is the code of tutorial.unhosted.5apps.com.
Put this code in the root of a domain on a webserver (if you run it from a file: address or in a subdirectory, the OAuth will not work).
Make sure you have your browser console or Firebug open when playing with it, so you can see what's happening.
Also don't forget to check out the annotated source code!
Come to our chatroom, which is #unhosted on freenode.
Feel free to use this code under MIT or AGPL license.