A lot of people like to try to trick one another with a lot crazy things on April 1st. I'm not really into that, so you won't see some big report on how I've been drafted into the army, or how Merrin is being sued for plagiarizing her blurb (although that would be funny, now that I think about it!)
Instead, for April Fool's web hijinks, you'll just have to go check out Robyn's site, Chris's site, or Metafilter. I'm sure there are others. If you run across them, please post in the comments so I can check 'em out.
Finally, check out the Top 100 Hoaxes of All Time.