I am constantly amazed each time I visit CSS Zen Garden. Created by Dave Shea, CSS Zen Garden is a site that defines itself as "a demonstration of what can be accomplished visually through CSS-based design." The objective of the site is to provide a resource for designers to point out the benifits about CSS-based design.
The method is straightforward. Download the HTML and CSS and "modify the style sheet in any ways you wish, but not the HTML." The outcome is anything but ordinary. Each interpretation and modification of the style sheet is so different from the one before it and the one after it. Ideas seem to go for ever and ever.
It brilliantly illustrates that designers are only limited by thier own creativity. And how imformation with strict guidelines can be interpreted in so many ways.