Would Google put these adverts on:
Google http://www.google.com
Microsoft http://www.microsoft.com
10 Downing Street http://www.number-10.gov.uk
Google Fun http://www.googlefun.info
The White House http://www.whitehouse.gov
By the way, it's very easy to cheat at this game by viewing the source of the page, as the test URL is passed to Google via an IFRAME. But the only person you're cheating is you, so there's no point unless you're incredibly sad.