For some fun reading today, check out the top 100 hoaxes of all time at The Museum of Hoaxes. These scenarios are all large-scale pranks that were played upon the foolish public at some point in history. They are actually very funny. And no, the link is not an April Fool's joke from me...they just seem to be really bogged down today!
Remember a few years ago when a local radio station announced that the local water source had been infected with di-hydrogen monoxide? (That's the chemical name for water by the way, if it's been a while since your last chemistry class) The mass panic that followed was truly ridiculous.
Have a fun day!