April Fools Day

Top 100 April Fool's Day Hoaxes of all Time
http://www.museumofhoaxes.com/hoax/aprilfool/

Their #1 Hoax is the 1957 BBC broadcast informing England that the Swiss are harvesting a bumper crop of Spaghetti.

This was accompanied by video footage of peasants pulling strands of spaghetti down from trees.