It's an unseasonably balmy 30 degrees on a picture-perfect Saturday morning on Phillip Island; somewhere close by, thousands of little penguins are preparing themselves for their Saturday-evening performance, while one of the southern hemisphere's largest fur seal colonies is sunning itself on the island's rugged south-western cape.

A little further east, surfers are enjoying idyllic off-shore conditions, riding head-high breakers along the island's endless southern coastline. Others have enjoyed a sleep-in and are only now tucking into bacon and eggs done 100 different ways at one of Phillip Island's many cafes.

Meanwhile, I have my face stuck in thick, chocolate-brown mud that smells even worse than it looks. A network of tightly strung wires 15 centimetres or so above my head traps me, completely enclosing me in a cesspit of wriggling, sweating bodies.

But there's far worse around the corner - the Arctic Enema. Forced to jump into a pool of icy water, I scuttle among icicles and under a log to make it out the other side. I'm then back in another pool of water, but this one is surrounded by electric cables, several of which pump thousands of volts of electricity through my body when I accidentally touch them.

That I'm doing this on my weekend might not reflect favourably on me, but the fact that more than 20,000 others - the vast majority from Melbourne - are right beside me in this hellish 20-kilometre obstacle course might suggest something about society as a whole.

What's happened to us? Did modern life get too easy (in the First World, that is)? Are we all repressed hunter-gatherers without a field to plough or an animal to spear, looking for challenges that suburbia doesn't offer? On the evidence, the answer is a clear "yes".

The "fun" I'm experiencing is part of a phenomenon sweeping the world called Tough Mudder. At last count, more than half a million people worldwide have tackled the obstacle courses, which are designed by British Special Forces to test strength, stamina and mental grit. Tough Mudder is fast becoming the world's premier adventure-challenge series, and it's only just getting started in Australia. The Phillip Island event in 2011 was the inaugural Australian Tough Mudder, followed by events across the country. Organisers expected 10,000 people to attend the Phillip Island debut; instead, the number was more than double that.

Tough Mudder is proof that the notion of a weekend away with friends has undergone a radical transformation. I've hired a house on the water with 10 friends, but on a Friday night away, we barely touch a drop of alcohol.

Dinner in Cowes is a carb-loading affair - astute businesses have recognised Tough Mudder as a potential cash cow and are advertising pizza-and-pasta nights.

Hundreds of diners in very tight T-shirts scramble for tables, while clever business owners operating nearby stay open until late to sell last-minute sports apparel to less-prepared participants.

The next morning, there are traffic jams on the way to Tough Mudder as thousands of Victorians clamber for their turn to get electrocuted, caked in mud, bruised and broken.

The widespread appeal of Tough Mudder is attributed to the fact that taking part is easy for your average suburban joe or jill. Most sporting events cater to elite athletes in distant locations; Tough Mudder is relatively cheap to enter, is held close to major cities, and anyone can enter.

What's more, there are no winners, participants must compete as teams - no individual is allowed to finish alone - and no times are taken.

As I make my way oh-so-slowly towards the last two obstacles, I watch hundreds of fellow Melburnians try to climb a three-metre-high wall caked in mud. The crowd groans in unison each time a body crashes into the woodwork, but the cheers that follow every time an unfit participant makes it to the top make me feel all warm and fuzzy.

Love it or hate it, Tough Mudder brings us together. There's a sense of camaraderie that shocks participants when they're all thrown together and forced to help one another reach the finish line. It's got me all choked up, though as soon as I get all this mud off, I'm off to a beach, a pub or winery.

FAST FACTS

Tough Mudder is on in Mulgoa, NSW, April 13 and 14, on the Sunshine Coast August 17 and 18, and back at Phillip Island September 14 and 15. Early-bird entry costs $105, with the price reaching $180 for the latest entries. See toughmudder.com.au for locations, all prices and to register.