For reasons I won't go into, I was looking for a line from the film 'The Elephant Man' and came across this site. Let's ignore the fact that a website about quotes in films had no quotes from this film - take a look at the ads on the right.
Now ... AdSense is meant to serve up ads that are in sync with the content of the web page - but can you find a connection between anything on this page and windows or double glazing? And - in case you are wondering - no, I haven't been searching for, or looking at, double glazing websites in the recent past [Google tracks your web usage to deliver 'relevant' ads].