* Danny Boyle's opening ceremony hours away
* Celebration of "Britishness" may baffle some
* Big crowds flock to Olympic Stadium
* Excitement mounts in Britain and abroad
By Mike Collett-White and Paul Casciato
LONDON, July 27 The world's spotlight turned to London's Olympic Stadium on Friday where the opening ceremony kick starts the 2012 Games with an eccentric and exuberant celebration of British history, art and culture.
Huge crowds flocked to the state-of-the-art arena in the Olympic Park, a sprawling network of sporting venues, athletes' accommodation, media centres and restaurants built in a previously run-down area of London's East End.
"The atmosphere is amazing," said Rebecca Simpson, a 21-year-old dancer due to take part in the ceremony. "The crowd is buzzing and it's amazing to be a part of something so big. I'm really nervous but nervous-excited."
Among the 60,000-strong audience watching the event, which kicks off at 2000 GMT, will be celebrities, ordinary Londoners, dignitaries including U.S. First Lady Michelle Obama as well as presidents, prime ministers and European royalty.
More than a billion more people around the world will watch the official start to 17 days of drama when more than 16,000 athletes from 204 countries will contest sport's ultimate prize - Olympic gold.
An effusive London Mayor Boris Johnson was typically flamboyant in his attempt to sum up the mood.
"The excitement is growing so much I think the Geiger counter of Olympo-mania is going to go zoink off the scale," he told crowds in London's Hyde Park.
Oscar-winning "Slumdog Millionaire" director Danny Boyle has masterminded the show, which is costing 27 million pounds ($42 million) to stage, less than half the cost of the Beijing extravaganza, and will last nearly four hours.
Entering the stadium, the flood of spectators will first see the opening set, a recreation of a British pastoral idyll complete with grassy meadows, fences, hedges, shepherdesses and live animals including sheep, geese and dogs.
At one end of the stadium stands a grassy knoll topped by a tree and at the other a giant bell that will ring out. In front of each is a "mosh pit" of people conjuring the spirit of the Glastonbury music festival and Last Night of the Proms classical concert.
"ISLE OF WONDER"
Boyle's colourful and sometimes chaotic vision aims to create a kaleidoscope of what it means to be British, an approach that could appeal to the home audience but leave many foreign viewers scratching their heads at times.
Some visitors from overseas, however, were confident that he would strike the right tone at a Games where the motto is Inspire a Generation.
"I have always wanted to go to the Olympic Games, and since it's in England I thought it's now or never," said Sigbritt Larsson, a 68-year-old from Sweden who paid 150 pounds ($240) for a ticket.
"I think it's going to be terrific because the English are so clever, you know the humour," she added. "I heard on the radio that the theme is generosity which is fantastic."
Boyle has been at pains to encourage 10,000 volunteers taking part in the show and tens of thousands more who attended rehearsals this week to keep its content a surprise.
That has not prevented details being leaked through Twitter, Facebook and the mainstream media.
Entitled "Isle of Wonder" and inspired by Shakespeare's "The Tempest", the show takes viewers on a journey from what poet William Blake famously called "England's green and pleasant land" to the "dark Satanic mills" of the Industrial Revolution.
Divided into three main sections, it will also celebrate the National Health Service, cherished by Britons despite being a political hot potato at a time when austerity measures have forced major spending cuts.
Spectators will be urged to join in traditional sing-a-longs, beloved by East End pub-drinkers, and help to create spectacular visual effects at an event that sets the tone for the sporting spectacle.
Ex-Beatle Paul McCartney will be among the many performers on the night, but the biggest secret of all - who has the honour of lighting the Olympic cauldron at the end of the show - remains a mystery. (Additional reporting by Paul Casciato, Stephen Addison and Matt Falloon, editing by Peter Millership)