On the April Fool's Day episode of Hannity, former co-host Alan Colmes appeared with a modified into to a faux show called Colmes. The humor, such as it was, was rather strained, but delivered with finesse by Colmes. The sad thing is, while Sean Hannity might find this stuff humerous, I also think he really believes it.
On the other hand, there are rumors that Hannity is puppeted by the less TV-friendly Mark Levin, and that Hannity off-camera thinks that all of this stuff is just a lark. In any event, while the scripted bit was cute, there really was no need to change the format to be in line with April Fool's Day. Hannity plays the fool nightly.