Pokemon Go has been the runaway success of the summer but why is it that some games, hobbies and activities become crazes while others do not? Is there a secret formula? Johanna Basford, the illustrator behind the current adult colouring book craze and Cheong Choon Ng, who invented the Rainbow Loom, explain how they managed to get their ideas off the ground and loved by millions.

We hear from psychologist Ben Michaelis that insecure people are more likely to engage with crazes than people who have a lot of self-confidence. Matthew Alt, co-founder of Alt Japan, a company which produces English versions of Japanese games, explains why so many childhood crazes of the last 30 years including Transformers, Power Rangers, Tamagotchi and Pokemon started in Japan.

Presenter Aasmah Mir also takes a trip down memory lane, trying out hula-hooping at a class in London after enthusiastically abandoning the fad 30 years earlier. Is she any better now? Hula-Hoop teacher and performer Anna Byrne explains why the craze is making a comeback.

But not all fads are harmless fun. Sometimes playground crazes can go wrong and have devastating consequences. Sabrina Lippell talks openly about the tragic death of her twelve-year-old son William Stanesby after he took part in the so-called ‘choking game’ that encourages participants to restrict their airways.

(Photo: A hand holds a phone showing a Pokémon character on screen. Credit:JoeyPhoto/Shutterstock)