Some would say they are brave, or bold - or insane.
They risk everything - livelihood, relationships, careers, even health and well-being - to follow their passions. They are ridiculed as dreamers, tilting at windmills - and success can bring its own barbs.
The line between kook and entrepreneur is fine and these chosen few tread carefully.
Take Denny Reid from Waiheke Island. Thirty years in New Zealand have left the Canadian native with a thirst for adventure and a passion for aircraft design.
Not just any aircraft - Reid's Aquaduckt is capable of road, snow, water and air travel.
"Why drive down the motorway to the airport? Why not use the motorway as your runway and take off? If the motorway is unavailable, use the harbour instead."
Reid, a long-time glider pilot, has designed a scale model of his craft and has been invited to show it at the Geneva Motor Show by Swiss prototype specialists Rinspeed.
"I'm hoping to secure sponsorship just to get to the show and then talk to people there."
For Reid, the craft is not just a pipe-dream. "It's lightweight, it's quick, it's affordable."
He has been approached by the United States Navy, discussed testing with Nasa and been in talks with Britain's Ministry of Defence.
But plans to travel to Europe and the US to talk to the military came to nothing after the September 11 terrorist attacks in 2001.
Still, Reid hopes that the trip to Geneva will stir things up again - he just has to get there.
Bruce Simpson is one of the original backyard rocket scientists.
After tinkering with his jet-powered sled, setting up one of the world's first online news agencies (7am.com) and keeping the IT industry on its toes with his daily online column at the Aardvark website, Simpson decided to show the defence industry how to build a cruise missile for less than US$5000 ($7000).
Needless to say, he was inundated with visits from overseas TV crews.
Simpson travelled to the US and entered into a heads of agreement with an unnamed defence contractor interested in his X-Jet engine.
But he says the New Zealand Government did all it could to scupper his plans and his licensing deal fell through.
"Having publicly admitted that the project broke no laws, thereby making it very difficult for them to simply shut it down by direct methods, the Government appears to have broken their own laws in an attempt to ensure that I can no longer continue this project - and, as perhaps a purely punitive step, ensuring that I can no longer even continue developing my jet engines or maintain my websites."
Attempts to contact the Government for comment on the claims were stymied by Christmas.
Simpson's project is on hold, although he says he has built a missile and hidden it somewhere in New Zealand. Most recently, Simpson was in Britain to help to build a jet for the television series Scrapheap Challenge.
Boats, by definition, are amphibious, so it was somewhat surprising when the former directors of local computer assembler PC Direct fronted up with a new company making amphibious boats.
David McKee Wright, chief executive, and founder Maurice Bryham, now chief operating officer, are certainly good at raising awareness as well as capital.
Sea Legs gets a lot of publicity for its "novel" invention. The company has even applied for a US patent for what is in effect a 5.6m rubber-ducky boat with wheels.
At nearly $100,000, it is not the cheapest inflatable on the market. Still, the wheels are direct-drive so you can sit in your boat, trundle down the ramp into the water, retract the wheels and head out into the harbour, all without getting your feet wet. No guarantees once the waves start lapping, though.
The company said recently that it had orders for 15 boats and had delivered 10, and that it would build a jet-boat version. It has also produced a profit for the first time in its varied and long history, which has to be a good thing.
Who hasn't had that frustration of getting into the car and finding the battery is dead?
Former policeman Peter Witehira set up Power Beat to design and build a car battery that never runs flat.
From that humble beginning, he has built a company that specialises in the obscure, the unusual, the off-beat.
Power Beat's first product, the intelligent car battery, included a system designed to ensure some portion of the charge always remained in the battery. Leave the headlights and radio on overnight and the Power Beat battery would still have enough charge left to start the car.
So revolutionary was the design that the battery became the first New Zealand product to win R&D magazine's R&D100 award in 1994.
The second product to win is another Power Beat initiative, the Deep Video Imaging 3D monitor.
But it has not all been plain sailing. Power Beat's legal tussles date back almost to its beginnings, and investors have come and gone from the Waikato company.
Witehira fell out with The Warehouse founder Stephen Tindall over his investment in the company and after a bitter court battle, the two went their separate ways. But Power Beat continues to introduce new products to supplement its lineup.
The company website includes a prototype data storage device that can hold an entire movie in a cube that doubles as a battery, and the MegaMantis optical data transmission device, which Witehira claims will provide abundant and cheap bandwidth.
Not all backyard boffins work in the technology field. No 8 fencing wire, after all, is all about farming and the backbone of the nation has provided its fair share of innovators.
Ken Lopes has been fighting the farming establishment nearly his entire working life, man and boy. He took over the family home-kill business when he was still a teenager and has been seeking that perennial Kiwi icon, the good steak, ever since.
Lopes has devoted his time to one breed of cattle, the wagyu (Japanese beef), and in trying to convince New Zealand farmers that breeding more wagyu would be a good idea.
"They've got less cholesterol than chicken. The fat has a higher ratio of monosaturated fat than anything else. The Japanese love the steak and pound for pound it's the most expensive beef on the face of the earth."
Wagyu breeders worldwide face scepticism from their dairy-cow brethren but Lopes is not fazed.
"I took a look at the milk they produce, too. It's got more calcium and less fat than regular milk by a long chalk."
New Zealand has a breeders' association, as do Australia, Canada, Britain, the US and a number of European countries. But perhaps because of his fervour, Lopes is considered something of a loner.
The mad, the bad and the just plain gifted
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