For some, the thought of a room full of strangers all laughing their heads off at nothing will cause alarm bells to ring, triggering images of new age bearded hippies resplendent in tie-dyed clothes, socks and sandals.
However, a growing number of people are signing up to laugh en masse -- at nothing -- in the hope of a health boost delivered with a smile.
Laughter yoga, the therapy which promises every health benefit from a strong heart to a slim waistline, is not necessarily something to tickle everyone's funny bone.
However, its proponents say nearly everyone can benefit from having a good regular chuckle, and hope it will spread throughout the country, from the boardroom to the hospital ward.
Auckland-based Malcolm Robertson is a registered clinical psychologist who last year did a five-day course in leading laughter sessions.
It took a while for the self-confessed cynic, and "scientific brain", to relax among a group of 25 all learning to laugh as therapy from laughing doctor Madan Kataria.
"It was definitely a life changing experience," Mr Robertson said.
Now, Mr Robertson leads a weekly laughter session in Ponsonby, Auckland, which he says has grown from a few friends and family to around 30.
He had long been interested in the beneficial effects of positive emotions on people's wellbeing, he said.
As a clinical psychologist, he said he knew "quite a bit" about what made people unhappy.
"But positive emotions tend to trump negative ones if we have them often enough," he said.
There was a vast body of scientific evidence to show regularly laughing did have health benefits -- it relaxed the muscles, easing stress, invigorated the heart rate, and improved the immune system.
What was interesting was that people seemed to gain the same benefits whether they were genuinely laughing or just faking it.
"If you are faking laughing, the breathing and physical exertion is using exactly the same muscles," he said.
Whether a person was honestly tickled, or just going through the motions, the body experienced the same sensations and benefits -- as did the mind.
"The body is trumping the mind by starting to laugh without any reason -- it can actually make a person more joyful.
"And you start off simulating it, but it becomes real because where are other people around also laughing -- it's infectious and always turns into real laughter."
Laughter yoga combines laughter with yogic breathing exercises to provide one-hour workout sessions that include 30 minutes of laughter.
Mr Robertson said the main aspect laughter yoga shares with traditional forms of yoga is the focus on the breath -- laughter makes people breathe more deeply, which has a raft of benefits in itself.
"As a psychologist, that's the first I would get people to do," Mr Robertson said.
"Get people to breathe more deeply, get more oxygen to the brain, help them relax."
Laughter yoga advocates say it exercises the heart, diaphragm, abdominal, intercostal, respiratory and facial muscles, with 20 minutes providing a workout equivalent to 10 minutes on an exercise bike.
Among other things, it strengthens facial muscles and reduces wrinkles, leaving people looking younger, improves cardiovascular health, reduced blood pressure, boosts body's oxygen and energy levels, as well as immune cells that attack cancer, infection and viruses.
It releases endorphins, a natural pain killer, stimulates the lymphatic system and boosts the immune system, and reduces levels of stress poisons 50 per cent or more in minutes.
And the positive effects came at no cost, Mr Robertson said.
"There are no side effects -- it's not medication, not talking therapy.
"We just leave our minds at the door and engage on what is a cardiovascular workout."
The classes are free -- laughter should always be free, Mr Robertson said.
He envisaged the therapy moving beyond the community centre where he holds his classes.
"It needs to grow in all the places where laughter is missing -- old people's homes, organisations, hospitals, that sort of stuff."
Laughter yoga began with a group of five in Bombay, in 1995, and has now spread to 5000 clubs in 53 countries.
Dr Madan Kataria, an Indian medical doctor dubbed the Guru of Giggling by The Times, started the groups with his wife after becoming interested in the health benefits of laughing while writing an article on it for a medical magazine.
Speaking to NZPA from South Africa, Dr Kataria said when he started, very few people laughed in the big sprawling city.
Life was "very stressful" in Mumbai, he said.
"We started out by telling jokes, but after about 10 days, we ran out of jokes," he said.
"So we said, let's laugh without jokes."
Now, 12 years later, Dr Kataria said he didn't remember the last time he had a cold.
Dr Kataria is visiting New Zealand this month, and will hold an information seminar and laughter yoga practice in Auckland.
There will be a public meeting on Friday March 9 from 7pm to 9pm at Jubilee Hall in Parnell, Auckland, and a two-day laughter training workshop on Saturday March 10 and 11.
Persons wishing to become laughter yoga leaders can participate in a training course in Auckland.
Dr Kataria said he hopes the practice will spread, in the manner of an irrepressible bout of the giggles, throughout New Zealand.
Information for the two-day course is available online at www.laughteryoga.org.
The Ponsonby Laughter Club is on every Saturday from 11-11.45am, at Ponsonby Community Centre. Contact is Malcolm Robertson on 021 02333 131 or firstname.lastname@example.org