They have formed high-fiving guards of honour to bid adieu to spectators and set out the hurdles in the Olympic Stadium with the precision of ballet dancers. They have placed plasters on grazed knees and stickers on excited schoolchildren. But most of all, they have given London 2012 its defining feature.
The 70,000 volunteers, or Games Makers, of the Paralympics and Olympics yesterday received the latest in a long line of votes of thanks when London Mayor Boris Johnson, with typical verbal aplomb, said they had dispensed "crop duster of serotonin" over the capital this summer.
From the job seeker from the West Midlands who travelled 2,000 miles to volunteer in the Olympic Park but did not see a second of live sport, to the dry wit of a Games Maker directing crowds to the Open ing Ceremony which became a YouTube hit, the volunteers have presented a big-hearted side of London it barely knew it possessed.
But amid the purple-shirted Feelgood Army that has pulled off the improbable triumph of turning London into the sort of city where for a magical eight weeks strangers talk to each other on the Tube, the satisfaction at a job well done was tinged yesterday with a sense of grief that it is all coming to an end.
Grandmother Grace Johnson, 62, who in ten days of volunteering on the Olympic Park has changed a nappy for a stressed-out mother and run 100 yards to reunite a teddy bear with its owner, said: "It's a bit back breaking. You get up at 5.30 and you don't stop but the camaraderie is fantastic. I think we'd lost sight of the fact that people respond to a bit of human warmth. I'm going to be a bit bereft after this. I'll have a little cry when it's all over."
The powers that be are hopeful that many of the volunteers, who between them have contributed eight million hours of free labour without which the cost of London 2012 would have been prohibitive, will offer their services to clubs and community groups, along with thousands of others who according to polls have been inspired by the Games Makers' example.
Mr Johnson, speaking at a reception in North Greenwich Arena to thank volunteers, said: "The important thing now is to look forward. We have to think about how to keep the energy in the volunteering life of the city."
In return for free meals and pre-paid Oyster cards, professionals from multiple backgrounds have given up their time and salary to join the London 2012 party. Aidan Robinson, a chiropractor from Doncaster, who helped British servicemen recovering from devastating injuries suffered in Afghanistan, worked in the polyclinic treating athletes in the Paralympics, and said: "Whatever I gave up was more than worth it."
With one Games Maker vowing he will be buried in his distinctive uniform, those who have indeed made the games will at the very least take away the satisfaction of having provided five million lifetime experiences.
As the volunteer whose loud hailer-delivered wisdom outside the Olympic Park became a YouTube hit, put it: "Some of you will say, I watched the Olympics. I'll say, I listened to the Olympics from outside and I heard a bit. It was faint but I still heard it. I heard them having fun and celebrating and I felt happy inside. I felt a warmth in my heart and I carried on."