One thing I did with it was create a Web site with recipes on it. The recipe files didn't have any actual content, everything was stored in the metadata. I had the Rules file set up so that they would run the Recipes through a layout that would expand them to HTML (consistently), then that was run through the normal page template.
It also used a preprocess rule to generate fresh items "on the fly" that serve as indices for each recipe type. Again, no content - the Rules file is set up so that the artificial items get all their content from a layout before being actually layouted with the site template.