It's that time of the year again, when you no longer can trust the news... oh wait, I guess you could never trust the news... Anyway, here's a list of some April Fool's jokes that I've come across this time around:

Opera Facial Recognition
http://labs.opera.com/news/2009/04/01/

Google CADIE
http://www.google.com/intl/en/landing/cadie/index.html
http://www.google.com/intl/en/landing/chrome/cadie/
http://mail.google.com/mail/help/autopilot/index.html

Read your email in Metacity
http://blogs.gnome.org/metacity/2009/04/01/squib-of-the-day-read-your-em...

Even CNN got in on the action:
http://www.cnn.com.news.donedev.com/Chiptune-composer-to-lead-Astral-Mus...

Those of you who listen in on the Bazaar dev list would find this one funny.
http://www.python.org/dev/peps/pep-0401/

PHP on Rails Framework:
http://phails.com/

Enjoy!