The joke of 2009 is the Chrome 3D http://www.google.com/intl/en/landing/chrome/cadie/.
Since 2000, Google has been launching jokes on April Fool’s Day. The first one was the MentalPlex. The MentalPlex is a Google search engine able to read your mind and guess what you want to search.
In 2002 Google announced that the secret of their system is that they are using pigeons to rank the web pages in their search. The PigeonRank was developed by Larry Page and Sergey Brin at Stanford University.
The April Fool’s joke of 2004 was the Googlunaplex. Google was hiring engineers to work at the new station they were building on the moon.