New Olympic Games chapter to be written in London

Who will be the new hero? What will be the $1bn image? After a tortuous journey, we're about to find out

It is entirely fitting that it should start with a stopped clock. At nine o' clock tonight, when that grand timer in Trafalgar Square – which had almost failed to start – finally reaches zero, it is indeed the beginning, but it is also the end.

The end of "out-of-control budgets", the end of the "ticketing fiasco", the end of the "security debacle", the end of "question marks still hanging".

The end of all the politicising, and the beginning of what you could be forgiven for forgetting it is all about. Finally, the suits are off. Behold! At last, the lycra. Let the Games begin.

The running, the jumping, the synchronised swimming, the unsynchronised swimming, the rowing, the shooting, the taekwonding, the pommel-horsing and every other feat of spectacular endeavour, starts now.

For a short time, we still have the raw excitement of not knowing what new chapters London will contribute to the Olympics story, the one in which Usain Bolt almost walks over the finish line to smash the world record. Or where Kelly Holmes's eyes widen as she realises she's finally taken the last chance she will ever have. Or where a diminutive child gymnast lands with a perfect bounce on a mat, confounding the scoreboard operators, who don't know how to display a perfect 10. What will be our billion-dollar photograph? It is a tantalising prospect.

And one, after all, that will be over fairly soon. It is not a long time, two weeks, when you think of what passes in seven years. Where were you, seven years ago, when Jacques Rogge opened his envelope on a stage in Singapore, and read out the word "London"? When Lehman Brothers was about to report its biggest-ever profit, and not many of us had heard of a politician from Hawaii with a foreign-sounding name? It is in these two weeks, not the previous seven years that, where once stood piles of discarded fridges on top of millions of tonnes of toxic earth, hundreds of the planet's most talented, most dedicated and for the most part rather young people , will be going about the business, in front of a watching world, of determining what does or doesn't get written on their gravestones.

Things will, inevitably, go wrong. Trains will be cancelled, platforms rammed, taxi meters will tick up towards eternity while the traffic never moves and the big boys zoom past in their BMWs on their way to some other segment of the Greatest Show on Earth to which you probably haven't got a ticket. But just for a short while, try to be nice. After all, we've got guests.

Jamaica House with its jerk chicken stalls, and giant Bolt-watching screens is installed in the O2 Arena, Russia Park, with its outdoor skating rinks in the middle of August, is open for business in Kensington Gardens. The Swiss have taken over the Glaziers Hall in south London and are inviting the world to the Bernese Games next weekend, with promises of "folk wrestling" and "cheese rolling" contests.

The giants of the American basketball team are stalking the streets of the West End. Slovenian swimmers are furiously tweeting pictures of themselves on Tower Bridge. Wimbledon's Centre Court has been turned temporarily fuschia.

The Prime Minister is eagerly awaiting dignitaries from all around the world at his pop-up "Business Embassy" at Lancaster House, where with the backing of a £7bn advert in the East End, he hopes to tie up dozens of massive deals for British companies overseas. One of the many issues around the seeming scarcity of tickets was that no Olympics had ever seen the sort of demand from foreign countries to come to London.

Despite the cavalcade of corporate sponsors that have both blazed its trail and followed in its wake, the Olympic Torch has been greeted with a tidal wave of goodwill on every step of its 70-day, 8,000-mile journey. Among the crowds who waved it off from Land's End on Day One was a sexagenarian man dressed as a Beefeater waving a giant plastic matchstick. It was just one of a thousand displays of the sort of British eccentricity that Danny Boyle has promised to, amongst other things, show to the watching world tonight, and which according to the IOC President Jacques Rogge, contributes to "a fascination with your country, all around the world, that you probably don't realise".

The buzz words of the Games, that have been so marvellously denuded in the BBC's Twenty Twelve – Legacy, Diversity, Sustainability – will re-emerge later this year and stick around for decades to come, but in the meantime, there is just the great attraction of sport, and the irreducible centrality of the contest. The teams, or the individuals, in a fair fight which only one can win.

So finally, if you really don't think the Olympics coming to your capital city when it is, for the time being at least, one of the greatest cities on earth, is not something worth telling the grandkids about, do bear in mind that there might just come a point at which they'll put two and two together, and ask you about it.

You have two weeks to decide what you want to say back to them. If it's: "You would not have believed the traffic!" or "Oh the queues to get on the Underground, the queues! The queues!" then brace yourself now for the crystallising realisation in their unborn eyes that granny or granddad might not be all they're cracked up to be.