Members of the public take part in a 'Thriller' flash mob in the Point Village, Dublin yesterday

Never mind the zombie banks and ghost estates, the nation still loves to give itself an annual fright in a tradition going back thousands of years. But Hallowe'en – or Samhain, as it was called by our pagan ancestors – is gradually being appropriated by the great god Consumer. Cheap face masks, monkey nuts and hollowed-out turnips of old are replaced by elaborate fancy dress, exotic fruits and pumpkins.

Colm Moloney of Headland Archaeology is keen to remind future generations of a festival that has little to do with shopping, but stretches way into our pre-Christian past.

"Hallowe'en in Ireland has adapted some customs traditionally more associated with American culture. The 'trick or treat' aspect that involves children in costumes going from house to house is a relatively new phenomenon here."

Samhain, translated as 'summer's end' refers to the Celtic division of the year, and corresponded with the end of the grazing season for early pastoralist communities, said Moloney. It was marked by a huge feast just before the Celtic New Year falling at the start of November. Recent archaeological digs unearthed a number of fulachta fiadh (ancient cooking sites) in Co Carlow, dating back to 1500 BC, and there is speculation these were used for the seasonal slaughter of animals before the onset of winter.

While a lot of the original meaning of Samhain and All Hallows Eve (Hallowe'en) is lost, it's still one of the most popular events in the calendar because there remains in the Irish psyche an acknowledgement of the Otherworld, and that this is a time of 'crossover'. Or, at least an excuse for a day off work.

"The tourist market has cashed in on the old traditions, such as 'get away for your Hallowe'en break' – because it must be at least two weeks since your last holiday," said Tadhg Dushlaine, Head of Celtic Studies at National University of Ireland, Maynooth.

"But it is right that we now have a bank holiday, and a mid-term break, because these ancient celebrations marked that intermediate time between the old year and the new."

The mischief making of old in rural areas – such as gates taken off hinges, or donkeys improbably re-harnessed up to the cart through the fence – lives on in our modern bonfires and bangers. "In the past, when the church baptised a lot of the old pagan rituals, such as designating 1 November as All Souls Day, this became a very serious part of the year," said Dushlaine. "But for those in the market for a bit of devilment, it was also an opportunity to rebel against that authority. These days, you could call it anti-social behaviour. But that little streak of rebellion in the Irish is never far below the surface."

And forget the ancients – the opportunity to party before the winter darkness closes in has never been more relevant. The scariest monster ever, namely the big monstrous December budget, is waiting round the corner to scare the living daylights out of us.