text: The Knock Knock joke , or gnoona gnoona joke as it was originally called , was devised by Henndrick Driedler , a successful first world war stand-up comedian . It is said that he invented the joke whilst trying to return to his deaf landlady's lodgings . Each time he knocked on the door , the landlady would ask who was there , he would say Herr Driedler , at one point after she thought he had said Hair Dryer he realized the potential humor in the situation and sat outside writing down other jokes until the end of the war .\n'why did the chicken cross the road' is credited to an Irishman - Seamus O'Reilly who actually carried out scientific experiments to find out why his chicken crossed the road - after three hard years he concluded that it was indeed to get to the other side . However, at his lecture on the subject ( Birmingham 1897 ) his peers fell about laughing and so , after much deep thought , he re-invented his paper as a joke , which has become the classic we all know and love . His descendants live a life of luxury , living off the royalties of this single joke .