it's a piece of pee...
what you need to do is create a table to store the stories... add them into the table with codes to place the variables, such as $pluralnoun or $biganimal
Then, when someone loads the site, read through the story and list all the $variables from the story into an array.
Dynamically create a form which creates a text field for each variable, with the name="pluralnoun" or whatever.
Then post the form into a script that outputs the story. If the $variable names in the story match the field names in the form, the variables will automatically substitute into the when it is outputted.
hope that makes sense to you!
adam