But while defending the Earth from aliens will never be a pursuit worthy of Einstein, a new breed of games is earning the thinkers’ vote. Adventures, strategy games, even games that ask you to care for a computer pet hit the sort of cerebral note that makes for a wholesome Christmas game. These are the games without shame.

The first stop at the shops is Microsoft’s Age of Empires, just out in an edition called Age of Kings (ages seven+). In this epic game you rule the Franks, Britons, Celts or any one of 13 kingdoms, and build your tiny tribe into a world-beating force. You set your villagers to work chopping trees, building houses and planting crops. You evolve your technology, build armaments or speculate with resources. In this new edition, economics and diplomacy figure large and you can now achieve victory by trading with other civilisations; fighting to glory or building supreme defences. The bird’s eye view of men and women at work is impressive, as is the fact that your minions now talk in a range of tongues. The graphics are more functional, too, so you can board enemy ships to capture them. Another new feature is the tutorial that prepares you for roles such as Joan of Arc, William Wallace or Genghis Khan. If you’re ever at a loss to explain historical ideas, this is an astounding reference game.

Such is the depth of many games that a huge community of players exchange tips daily over the Internet. When Creatures (ages eight+) appeared, it too developed a cult following. But rather than trade tips, its devotees trade Norns - artificial creatures they raise and breed. Created by Creature Labs - www.creaturelabs.com - Creatures creates a world populated by ‘living’ virtual pets, a place that has seasons, weather and growing plants. The creatures have brains, digital DNA and a biochemistry so detailed the game has spawned research tool spin-offs. You teach the Norns, feed them and protect them from toxic plants. They’re funny, too: they talk in speech bubbles and soon tell you if they don’t like what you’re doing.

Just an hour after birth, they take a shine to the opposite sex and start breeding. Later, having passed on their genes, they die. Strange to say, the first time one of your Norn charges shuffles off its virtual coil, it is incredibly sad, which is a clue that here is no game with a set plot but an amazingly life-like model. New to the Creatures family is Creatures 3, with a bigger world, real ecology and real physics that lets objects fall and have momentum. It’s also easier to play - its starter family is already educated so at least they know they have to eat.

Alternatively there is Creatures Adventures (ages six+), which with its larger graphics is a better buy for the kids. Children care for the bright-eyed creatures, playing and even baking bread with them. They take photos to treasure special moments and when the Norn creatures die, they put them in a special corner of the garden. Children learn to cope with this, and they ask interesting questions - mostly about having babies.

Making the strategy game accessible to younger children is Legoland (ages six to 12), which puts children in charge of a theme park. Featuring favourite rides from the real theme parks such as the driving school, the game may be easy to relate to, but remains a business management game that asks players to build a park that draws in customers. Good designs are rewarded with new attractions, Lego sculptures and rides. Fresh and colourful, it provides challenging fun and continues the high standard of other Lego titles, three of which were awarded Gold Awards by the Parents Information Network (PIN) earlier this year.

Quality and good value are also top of the agenda in another new strategy title, Lego Rock Raiders (ages eight+). In this adventure, children use technology to mine precious Lego ore; they explore underground, decide on their tools and transport they want to use and generate reports from sensors that detect rocks, air quality and temperature.

Deep down below lurk hazards like poisonous gas and rock monsters whose food you are about to take. It’s all good fun of course, well that is until you make the monsters angry; weapons include a teleporter gun and a painless freezer gun. Defend yourself and the monsters shatter into loads of tiny ones.

Resource-based strategy games such as these tend to rate high on satisfaction, and lower on adrenaline. While there are more strategy games than you have life for, they come in flavours to suit all tastes: Railroad Tycoon (Microprose, pound;34.99) asks you to manage the railways; Sim City 3000 (Maxis, pound;29.99) to organise a city’s services; and Star Wars - The Gungan Frontier (Lucas Learning, pound;29.99) requires you to build a city and run an eco-system based on the latest film.And that is just three games - there are many more.

The beauty of all strategy games is their wealth of options that force you to make decisions continuously as you run out of food, money or materials or as a situation changes. If you get stuck, you can receive help from other players via Internet newsgroups or a dedicated website - both provide tips to move forward.

Countless variables means countless variation, which makes these games something of a full-time hobby. Just don’t forget to talk to the folks at home now and then.

Age of Kings (part of the Age of Empire series) CD-Rom Price: pound;39.99. Creatures. Price: pound;9.99. Creatures 3. Price: pound;39.99. Creatures Adventures. Price: pound;24.95. Plus add-ons available from Creature Labs website. Price: from pound;5. Legoland. Price: pound;34.99. Lego Rock Raiders. Price: pound;39.99.