German car rental company Sixt found a way to turn Google paid search results into a rudimentary- but highly effective- form of banner placement.  They used the three lines of text to create ASCII art, in this case of their rental cars (mietwagen). The case study is here:

http://www.bannerblog.com.au/2007/12/sixt_ascii_text_ads.php

If you go to Google.de the campaign is no longer active, so it appears Google has already banned future uses.  Thanks to Jacob Ford.

Misha Cornes