It's what they call aaaa-rt!

I have just been to the opening of Tate Modern's latest installation, a series of giant slides filling the vast Turbine Hall, and for those who think contemporary art consists of staring at pickled sharks or unmade beds and trying to work out what it's all about, being an art critic will never be the same again.

The installation Test Site consists of five large slides on which people can career from the upper floors to the bottom at up to 30mph, and I do not think it would be disloyal to suggest that there are plenty of people out there who would pay good money to see my esteemed colleague Brian Sewell swishing down on the ride of his life.

The work is by the Belgian-born conceptual artist Carsten Holler and there never was an artist more appropriately named. People did indeed holler: they screamed and yelled in a rather hysterical fashion, then got off at the bottom with a silly grin on their faces and wondered if they had time to do it all again. The biggest slide is 55 metres long from the fifth floor and while I am probably not equipped to pronounce on what it says on the human condition, or the debt it owes to contemporary architectural theory, I can report that it is great fun.

Fun, but bumpy. The slides are made of polished stainless steel, which might suggest you are in for a smooth ride. You are not. You bump along like you just hit pothole central and generally feel like you've just gone through the washing machine on the fast spin cycle. Then you are spat out and if you are lucky you are going so fast that you fly off the end and land on your bottom.

Hardcore thrill seekers should go to the faster, steeper fourth floor slide, which even features a slalom: just like the Cresta Run, really, although instead of the Alps flashing past it's the Salvador Dalis on the third floor. At least it would be if you could see anything other than a grey blur.

The inevitable question - although possibly not one asked by many of the slides' customers over the coming weeks - is: is it art?

Jessica Morgan, curator of the Tate, said the work was about the artist's use of space, the experience of people going down the helter skelter as well as the practical questions it asked about how we move around in and between buildings.

Oh yes, and she also said it was rather like sex. One did not inquire exactly what she meant, but she added "it's very addictive. the more you do it the better you get. It's really thrilling, particularly in the morning."

As for Holler, he said: "Going down can be like being under the influence of a drug - a thrilling experience but it is also a fast and efficient way of getting from A to B. It's a playground for the body and the brain. It's art and it's not art."