I've never been a fan of April Fool's jokes... they often tend to be mean-spirited (and I'm such a loving-giving type of guy). The internet has made it very easy to do great practical jokes. Some do it well, others not so much.
Case in point: Whole Foods. They get it. They know who they are, what they represent and who their customers are. So they came up with the perfect April Fool's homepage. Check it out, it won't be there long.
Found another one... not as clever as it is obvious and a dig at Twitter
I'm sure this will food a few people... (if only it were true) :
And hey, don't be douchebags... if you're going to punk someone, don't be an ass about it.