What is the best April Fools' Day joke you've ever fallen victim to?
Live Journals Writer's Block
Haha, hands down it has got to be the FreeBSD and NetBSD's pkgsrc: A strategic synergy for awesomeness posting on the FreeBSD Ports mailing list. I remember seeing it posted in the lounge on forums.pcbsd.org.
It took me a week to realize the original message had been posted April 1st :-)
Can you say, fooled "big time"?