According to a growing band of researchers, sociologists and health experts, playing is exactly what more of us should be doing. Far from being a frivolous indulgence, an emerging evidence base suggests playtime in adulthood may actually be critical to human development.
''From a biological and evolutionary point of view, social mammals have been hard-wired for play for hundreds of millions of years. It's a fundamental survival drive, not too dissimilar from sleep and dreams. Although we can survive into adulthood without it, we don't survive socially, emotionally, cognitively with any kind of fullness without having a healthy play background that continues throughout life. It is a sustaining, important part of being human,'' says Dr Stuart Brown, a pioneering play researcher from the National Institute For Play in California.
Whether it's dancing in the dark, rolling around on the floor with a pet, or just belting out our favourite songs as we strum the air guitar, play for play's sake is increasingly being shown to have significant positive effects in education, parenting, workplaces and even in fostering community cohesion.
The ''play ethic'' is deemed so significant that dozens of cities are starting to foster greater social interaction in public spaces.
London's Swing & Be Free project put swings into bus stops, encouraging incidental fun for commuters. In Montreal, a giant collective instrument made of 21 musical swings has been set up in the city centre. While in Stockholm, a piano staircase in a subway underpass led to a 66 per cent increase in people using stairs over the escalator. Proponents say the separation of play from work is no longer appropriate in a frenetic modern world where ''downtime'' is a rare luxury.
They believe incorporating fun into all aspects of our life is the key to happier, more productive societies.
Businesses such as Google, Lego and Red Bull are among those prioritising playfulness as the building blocks of creativity and innovation, with adventure playground-style office environments complete with scooters, hammocks, mini soccer pitches, lolly dispensers and tyre swings.
Employees at Melbourne-based firm iSelect enjoy a slide that dumps them into a ball pool.
Dr Brown, a psychiatrist who was in Australia this month for the Arts Health Institute's Play Up Convention in Sydney, believes play - which he defines as any activity which is deeply engaging, joyful, done for its own sake, and without consideration of time or an expected outcome - is the cornerstone of a healthy community.
But when play is absent, things can go awry. Dr. Brown's fascination began after extensive research into the backgrounds of violent inmates, including Charles Whitman, who killed 17 people and wounded 41 others in a shooting from the top of a tower at the University of Texas in 1966. The common theme among offenders, he discovered, was ''play deprivation'' as children.
The research backs up animal models that show play opens new connections in the brain, boosting social and emotional competency. Deprivation can cause problems with mating, stress, resilience and immune system deficiencies.
''The most successful people I've interviewed, and I've done several thousand of these, have had the opportunity to live their lives in harmony with their play nature,'' Dr Brown said. ''We know from a number of anthropological studies that in civilisations and cultures that incorporate a good deal of play there are increased co-operation, great altruism, more sharing and less violence. We're not there yet by a long shot in an industrialised, Western, materialistic culture but I think that with the public health and scientific backing play is now being shown, we will see transformational changes down the road.''
It's already happening in pockets in Australia. A 2011 trial of play therapy involving 35 nursing homes and 400 aged care residents, using clowns and ''humour therapists'', led to a 20 per cent reduction in levels of agitation among dementia sufferers, and significantly reduced the need for antipsychotic medication.
The program has since been rolled out at 70 aged care facilities. ''Smile Study'' chief investigator Dr Lee-Fay Low, from the Dementia Collaborative Research Centre at the University of New South Wales, said nursing home residents were often bored and lonely, with little chance to experience humour.
''Giving them an opportunity to play changes them. It gives you enjoyment, it gives you opportunity to express yourself and helps you make a connection with other people, and those are critical things for mental wellbeing at any age,'' she said.
Co-founder of the Humour Foundation's Clown Doctor program and creative director of the Arts Health Institute, Jean-Paul Bell, believes Australians are playful and irreverent by nature but we've lost touch with our true selves.
''Living in cyberspace is not grounding us in the way that organic play would do. It's that idea of getting down and dirty and making mud pies, sliding down a hill on a piece of cardboard so you're connecting your bum with the earth. Forget about how old you are, the incentive to play is a cradle to grave approach.''
But while once our playfulness would have been cultivated at an early age, these days overprotective parents, shrinking backyards and increasing pressure to achieve academic success are contributing to a reduction in play time for children.
Brown says this is why we must put play at the forefront of education, arguing that this ''flow'' is the optimal state for learning. He points to a growing number of play-based schools in the US which are seeing great results.
Here, programs such as ArtPlay - a creative studio at Melbourne's Birrarung Marr - are encouraging children and their families to express themselves through art, performance and inquisitiveness, which in turn can boost learning.
''Schools are very regimented in expected outcomes and testing these days and sometimes the value of free play is underestimated,'' said creative producer Simon Spain. ''We do workshops out in the backyard where we literally just go out and get some sticks and get people drawing in the ground. It can be simple and messy, you don't have to buy the fancy drawing pad and the pencils. Our sub-line is 'let your imagination out to play' because that's what sometimes is cramped. Ultimately what we're trying to foster here is the imaginative person who can imagine possibilities.''