Google seems to be testing “related” AdWords ads on the right hand bottom panel of their search results.
James Carswell noticed this and posted a screen shot of the related AdWords ads. I personally do not ever remember seeing such a test. Here is a sample of his screen capture:
I have seen something similar where Google placed related commercial results in place of the Google AdWords ads, but not showing related ads for related keywords in this area.
Postscript: A Google spokesperson sent me confirmation about this test:
We’re always experimenting with new features and tools to help users find information online. We’re currently testing a feature on English language versions of the Google search results page in which additional advertisements for related queries or refinements of the user’s original query may appear. This beta experiment provides users with a diverse set of relevant ads, and offers advertisers with relevant broad match keywords another opportunity to reach their target audience.