(via KingLudIC) If you want to fiddle around with Chris Crawford's Interactive Storytelling tool, you can download the alpha version on its website.
Apparently you cannot make fully functioning storyorlds, it's complicated and buggy. Why should you bother, then? Here is what they say:
Why should I bother?
We believe that storyworlds will be a major breakthrough in interactive entertainment. Early adopters will have a head start as the first creators of a new storytelling form. It will take months to fully grasp the Storytron technology and the sooner you get started, the sooner you'll be able to start creating storyworlds with it. There is so much for you to learn; we think that you will need several months just to get comfortable with what's already in Swat.
The file is really small (less than 500kb!), but you will need J2SE(TM) Runtime Environment 5.0 Update 6, which is around 16mb. So why not give it a go?