What makes a good April fools story?

It is April fools day and we are waiting for the stories to come in. But what makes a good Aprils' fool? The story needs:

Within the bounds of regular reporting: This is easy for general newspapers, a little more challenging for technical publications/technical blogs
Plausible: A reader must think: yes that is possible
Disguised: Best mixed with facts, so facts and fiction melt together
Falsifiable: With a little effort it should become obvious (most cases: nobody else reports it)

I'm blogging for a number of years now and had more or less successful entries:

Of course: Funniness is in the eye of the beholder

Posted by Stephan H Wissel on 02 April 2009 | Comments (1) | categories: After hours