Sleep deprived, rain-soaked and unpaid, London's army of Olympic volunteers - officially known as "games makers" - are surprisingly upbeat, and have won admiration for their work shepherding thousands of fans around sports venues.
"We're the pulse of the park, the heart of the Games," volunteers Emma Ward, a sports teacher, and Hannah Page, an administrator, cheered in unison at east London's packed Olympic site this morning.
Like other unpaid workers at the Games, the two women had taken time off work and travelled hundreds of miles to London at their own expense to help with the mammoth logistical task of hosting the Olympics.
Some are regular volunteers, who often donate their time to community projects, others want to be part of what they see as an historic and once-in-a-lifetime event, and a few cite burnishing their resume and making friends as a key motivation.
The volunteers often work gruelling shifts and sometimes have the privilege of free access to Games events, thought this is not guaranteed.
Whatever their reason for coming, their help, alongside cheerful soldiers and private security guards, has been highly appreciated.
"They've been positive and helpful. They're always visible. If you want to ask a question, there's always someone less than 10 metres away," said spectator Heather Brownscombe, 27.
Olympic organisers also heaped praise on the volunteers.
"Our brilliant volunteers seem to be having an extraordinary impact on everyone they get to meet," Paul Deighton, chief executive of the London organising committee (LOCOG), said on Sunday, day nine of the Games. "We are really proud of them."
There are some 70,000 games makers at Olympic venues across Britain, some coming from as far away as Canada and South Africa, doing everything from stewarding fans to translating and providing medical assistance.
The bulk are in London, which is now awash with Olympic helpers in their eye-catching red and purple sweatshirts and grey track pants.
The vast majority seem to be having fun. At a campsite a few miles east of the Olympic stadium, where hundreds of volunteers had pitched tents for 10 pounds a night ($16) or were sleeping in their cars, there was a jamboree atmosphere.
"I'm sleeping in a tent, I've been here for 10 days and it's been brilliant," said Sally Bucknole, 48, a college administrator.
"I was at the stadium last night and the atmosphere was amazing, it was electric. Tickets are hard to come by, so this is one way to get involved. It's a chance to see a little bit of history," she added.
The campsite is also a rugby club, and each night Olympic visitors from around the world join the volunteers in the clubhouse to cheer and sing as they watch the action on widescreen televisions provided by the club.
"It's a really good atmosphere, really friendly. It's not the usual London atmosphere where everyone keeps their head down and keeps to themselves," said Izzie London, 24, a volunteer and medical technician staying at the campsite.
The games makers applied for the role two years ago, and underwent interviews in which they were asked about their volunteering experience and assessed for their personability and competence.
Teacher and fencing coach Paul Caine, 44, had driven 280 miles (450 km) from Newquay in western England to help at fencing events.
"I've been up at 4.30 a.m., 5.30 a.m., but the adrenaline and excitement means it's OK," he said, tidying up in the back of his white van, where he sleeps on a mattress next to his bike.
Annabel Russell, 43, is one of the unlucky group of volunteers posted at transport hubs far from the Olympic venues in east London to direct visitor traffic, sometimes in the rain, using large pink foam hands to point the way.
"It's still wonderful even though I don't go into the Olympic venues," she said, adding that support and appreciation of her role had risen in tandem with British success in the Games, which has stoked Olympic hysteria across Britain.
"It's getting more rewarding each day. I'm getting texts and tweets of support and that's keeping me going," she said.
The enthusiasm contrasts with the cynicism, at least in the British media, in the months leading up to the Olympics, with many criticising the Games as too expensive or poorly organised.
"The media disses most things, don't they? We knew it would be fantastic," said volunteer Hillary Orr, 46.
The volunteers have not all been demonstratively cheerful, however. Perhaps the most famous so far has been a bored-sounding woman directing crowds with a megaphone.
"I cannot contain my excitement, everybody," she said in a video that became an Internet hit.
"Today is a special day. We are going to be telling our children's, children's, children's, children's, children about this day," she added in a deliberately humorous monotone.
A few volunteers have been over-zealous in enforcing Olympic venue rules - threatening to report journalists who do not make an official application to speak to games makers, or cracking down on those who stray only yards away from walking routes.
There is also controversy in some quarters over volunteers being exploited. The Olympics is a major commercial sporting event, drawing multi-million dollar sponsorships, and some believe they should be better rewarded.
"Huge money making organisation, we have bumped untold billions of tax payers money into it and you guys are mugging yourselves off so badly to work for free .... have you all lost control of your senses?" said an online forum poster, mhead bee.