Billy Connolly doesn't really like the Olympic Games. “A bit Nuremberg,” he said. Well, it's true that there tends to be an awful lot of flagwaving going on at both an Olympic Games and a Nuremburg Rally.

But it's really quite easy to tell the difference. At the Nuremberg Rallies, all the flags were the same.

At the Olympic Games here in Beijing, at the lowest possible count there are 205 flags: those of the 204 nations taking part, and the Olympic flag, which was absurdly goose-stepped to its flag pole with a classic John Cleese silly walk by the People's Liberation Army at the opening ceremony, as if to prove that Billy was right. All the same, he isn't. There should have been 205 nations, but Brunei somehow failed to get its athletes accredited.

I love biodiversity above all things. I have said as much many times when writing about wildlife. The Nuremberg Rallies were designed to promote a human monoculture: the Olympic Games are a celebration of complete failure by them - and many others. They tell us - they sing to us - about the boggling biodiversity of the human species.

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Nations, creeds, colours, shapes, sizes: all of them coming together because each person is good at a single strange and futile thing.

They can run fast, swim fast, fly through the air, hurl unlikely bits of stuff unimaginable distances, twist and tumble, strike balls with hands and feet and sticks, ride horses, sail boats, shoot guns, propel arrows, wield swords, lift up chunks of iron, thump each other, chuck each other about, kick each other in the crotch, jump over things, skip about with ribbons, stick their heads in the water and wave their legs in the air, ride bikes.

There are 28 sports altogether, and a great raft of sub-disciplines within. Swimming doesn't just take place in the pool: there is also an open-water swim, introduced for the first time since 1896, in which competitors will swim 10km at the rowing lake, though presumably they will get the boats out of the water first. This is swimming as a contact sport: Cassie Patten, British and a genuine medal chance, said she operates a three-strikes policy over contact in the water. “The first time it's an accident. The second time, I think, hmm. Third time I get 'em back.”

But swimming also includes diving, in which the ability to swim is little more than an acceptable bonus: the essence of the sport is not swimming but flying, albeit in a mostly downward direction. Swimming also includes the world's dirtiest sport, water polo. It used to be compulsory to wear two swimming cozzies, to maintain the decencies when one of them got untimely ripped.

The women's water polo invariably attracts big crowds, it being a ferocious contact sport in which the garments are regularly seized and tugged and torn and breasts are there for the admiration of all. Observers of the sport have a particular affection for a glamorous but terrifying player who went by the name of Giusy Malato.

And I still haven't mentioned the fifth discipline within swimming (open-water is separated from pool swimming), which is the glorious absurdity of synchronised swimming. I know it's silly: but you try it.

Not necessarily the make-up or the smile, but holding your breath for two minutes while performing all manner of extraordinary body shapes, and after that, carrying on for another three minutes.

Or consider the variety of humans required by the single discipline of running: from the musclemen who work to find eternal fame (or infamy) from less than ten seconds of action, all the way to the tooth-pick go-forever legs of the marathon runners who go for more than two hours, running each single mile faster than you could ever dream of doing even without the other 25 miles and 385 yards.

There are giants and midgets, ogres and pixies, fighters and fleers, every antithetical pair you could wish to come up with. Including men and women: long gone are the days when Baron de Coubertin, founder of the modern Olympic Games, declared that the purpose of women at the Games was to crown the winners with laurels; or the times when women were not permitted to run farther than 200 metres, because it was too far for fragile them.

And all of them dedicating their lives to these strange and, let's be frank here, completely pointless tasks. Not just a bit of their lives: in modern sport, there is no room for polymaths. To perform at the Olympic Games - not to win a gold medal, just to get there and have a go - is to make your sport not into a hobby or a pastime but the point and purpose of your life.

At the Olympic Games, every time you look at any athlete in any disciple on any day at any venue, you can feel pretty safe in saying to yourself: this day is the supreme moment of that person's life, the day for which all other days have been nothing but preparation. Now all that preparation counts for nothing as the event starts and the competitors enter the eternal now of sport.

What's the point of it all, then? Nothing, of course. Pointlessness is the point. It's not about getting fit and healthy, still less is it about peace and brotherhood. Sport at Olympic level is a search for a pure and perfectly pointless brilliance: a search for excellence for its own sake.

For the purpose of joy and glory, if you like. But that's what gets to me about the Olympics, and has got me for this and for the five previous summer Games I've covered: the biodiversity of excellence. How many ways can a human be brilliant?

How many ways can humans excel each other and themselves? There are a thousand medals on offer here at the Olympic Games: a thousand different ways of being brilliant, a thousand different ways of seeking perfection. And a few of them, just a few, actually find it.

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