April Fools' Day

April Fools' Day was a holiday celebrated on 1 April. On this day it was customary for people to play practical jokes and hoaxes on one another.

April Fool's jokes in the real world

 * An issue of the Doctor Who fanzine Dream Watch Bulletin said there was a sixth episode of The Dæmons planned which would feature the Master escaping UNIT.
 * An issue of Doctor Who Magazine reported that an attempt was made to colourise parts of The Tenth Planet.
 * 2009 - As an April Fool's joke, word circulated around the Doctor Who set that Michael Jackson was paying a visit. (REF: Doctor Who: The Writer's Tale - The Final Chapter)
 * 2010 - It was confirmed that Steven Moffat would return the Kandyman in the series finale but this was an April Fool's joke.