Speaking generally (because my own experiences are from further along the coast Eastwards)

Christmas is firmly divided into three distinct parts in Spain

Christmas itself is for the older members of the family - it's all about making your mums and dads and grans and grandads and aunts and uncles happy.

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New Year is for the younger folks. Many people enjoy family gatherings together and drink cava, canapes and have the traditional 12 grapes together when the 12 gongs at Sol (Madrid) sound. But after midnight, those youngsters, dolled up like prom dates, will clear off - either hitting the bars in town or going off to an enormous warehouse 'nave' for a pre-paid 'super fiesta' (expensive because drinks are included - although the lines to the bar are invariably loooong). They'll return at noon the next day or considerably later.
Visitors to any city should
- Make sure they have a supply of cava or Asturian cider - share it around with strangers! (It's the Spanish way!)
- Buy 12 grapes each a few days in advance (they can be hard to find). Peeled canned portions of 12 can be bought at this time - but this feels like a cop-out somehow.
- Dress up warm and get to a town square with a clock in it. Ask which square the locals will be using. (Kids here should be fine in many cities - but I wouldn't take them to Sol in Madrid which gets too crowded. Try asking a local family for advice)
- Be prepared to kiss a lot of people


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3 Kings Day is for children - pure and simple

On the evening of the 5th January there will be spectacular parades and carnivals through every city in Spain.
But there is much much more going on for children in the days leading up to the 5th. Every town and city will have a calender of events.
There is usually a formal reception for the visiting 3 Kings at the Town Hall. Fantastic fireworks are usually set off after the procession - generally from the Town Hall.
In Madrid the Arrival of the 3 Kings is treated as a State visit and the King & Queen come out to greet them. This gets covered on the News and given all seriousness.

At this time it is also traditional to eat Roscon de Reyes - but mind your teeth as little knick-knacks are secreted inside.

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As each city is different, and scheduled events in each can change a little from year to year, the best thing is to go to one of the larger Tourist Information Centres and ask them to provide you with a schedule and further advice. Stress that you want to know about events your children can take part in.

As I've mentioned before, don't expect much in the way of Sales and store discounts before the 6th January. Most children (and many adults) won't have received their big gifts until that morning.

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As long as you make a little effort to uncover what Andalucia has to offer, I sincerely hope you won't return with the impression that Spain is lacking in either tradition or atmosphere at this wonderful time of the year.