The Cheerful Insanity of Me

So, I was thinking, the problem with April Fool's jokes on the radio (or in many places for that matter), is that they keep telling you what the date is.

A way around that would be to have a joke involving it being a different day.

Which has got me thinking that, perhaps what they should do is just replay the previous days show and see how many people they could convince of a Groundhog Day style time loop.

Seems very obvious, so it must have been done. Anyone know?