Outdoors: The strange practice of 'sphereing' is as much fun as it looks

OK, so this is how it works. You get a giant inflatable ball, climb inside, then let your children push you down a great big hill at speed. Got that?

Sphereing - or zorbing - has gained popularity through its use in adverts for everything from online bingo to mobile phones. It looks like a laugh from the safe distance of your living room sofa in the way that, perhaps, bungee jumping or tombstoning might.

But, standing on a breezy hill in Perthshire receiving our safety instructions while being strapped into a harness, the reality was beginning to bite. Whose idea was this anyway? I decided to let the children go first.

Spheremania is the only group to run this kind of activity in Scotland, through Nae Limits, from a field somewhere near Dunkeld. I'd tell you exactly where it is, except I got lost twice trying to find it so my directions might not be up to scratch.

Even the big sphere kahuna, who has been driving there for two years from Dundee, still needs his satnav to find his way.

Still, once we had eventually parked the car in a patch of waste ground and climbed to the top of the hill, there was no going back. And since this kind of activity is weather dependent - they've done it in rain, snow and shine, but high winds might send you into the neighbouring river if you're unlucky - we'd already had our date with destiny cancelled once. As Elvis might have said, it was now or never.

The sphere takes two people at once - you can't take part if you are pregnant, suffer from high blood pressure or back/neck problems, if you're under 12 years of age or over 18 stones in weight. They've had former SAS soldiers cry like babies at the end and 80-year-old grandmothers whooping with delight. We wondered which category we'd fall into.

The two elder children went first, leaping through a small hole in the ball's outer wall then being securely harnessed at either end inside. Then it was simply a case of giving them a big shove and down they went, head over heels, until a row of haystacks at the bottom of the hill stopped their descent.

The roll only lasts about 30 seconds but, as I discovered when I went next with my 12-year-old, it feels a lot longer. He giggled from start to finish, I squealed with delight in spite of my determination to be cool. It felt surprisingly safe as we tumbled, leaving us with the giddy feeling I remember from summersaulting over and over as a little child.

And as we set off home with huge smiles on our faces, having had the best time we've spent as a family in months, we determined to book more rolls next time.

Sphereing , from 59 for two people for one roll, Nae Limits (08450 178177, www.naelimits.co.uk)

This article was first published in The Scotsman on Saturday, 21 August, 2010