I ran into a few of those when in SE asia many many moons ago. Usually occured around the first of the month which, funnily enough, coincided with pay day. Go figure.
Actually, this year IMO was pretty lackluster as far as april fools. The net jokes weren't all that great IMO although http://www.thinkgeek.com
has me rolling with tears in my eyes with gadgets like the WiiHelm, Super Pii Pii Bros, & USB Pregnancy test!
At any rate, I got at least one person at work hook line an sinker when I told him gas was at $2.00 a gallon just up the road. I had a least 5 people talking about it, but one called into work asking me to confirm which gas station it was.
I posted a bulletin on myspace stating that I was entering a convenience marriage with a stripper that needed a green card. I think only one person even noticed it.