list of Google April Fools Hoaxes

2000 MentalPlex http://www.google.com/mentalplex/

1. Error 01: Brainwaves received in analog. Please re-think in digital.
2. Error 001: Weak or no signal detected. Upgrade transmitter and retry.

2002 Pigeon Rank http://www.google.com/technology/pigeonrank.html

2004 Google Copernicus Center http://www.google.com/jobs/lunar_job.html

2005 Google Gulp http://www.google.com/googlegulp/

2006 Google Romance http://www.google.com/romance/

2007 Google Paper http://mail.google.com/mail/help/paper/index.html

         Google TiSP http://www.google.com/tisp/

refer http://www.epiphanysolutions.co.uk/blog/googles-april-fools-day-hoaxes-2000-to-2010/