April Fools' Day - On the Web

OpenOffice bought by MSFT http://www.openoffice.org/april-fools-day.html
Google Dating Service http://www.google.com/romance/

MSN Search Spoof http://www.msnsearchspoof.com/
MSDN Coding4fun April Fools' special http://msdn.microsoft.com/coding4fun/april-fools/