I've never hoaxed anyone and the only thing anyone ever did to me was put an elastic band on the trigger on the hose at the faucet so that when they turned the faucet on, I got hosed in my face.
I did have a girl I worked at a supermarket with who's brother told her that he overheard her boyfriend ask her dad for permission to marry her as a total joke because all she did was talk about her boyfriend. She kept pulling out the Martha Stewart's wedding magazine from the aisle. A few days later, someone updated me that she was so devastated when she found out that she called out of work for a few days to recover.
That's all I got. What do you have??
Here's some from the internet today:
http://www.chicoer.com/news/ci_22914380/april-fools-jokes-internet-pranks (I think the Skinny Jeans are funny (here's a
LINK to the AE ad)
An archive of historical ones:
http://museumofhoaxes.com/hoax/aprilfool/