You would not have thought it, but while you sit contentedly digesting your turkey and gazing at the telly, your brain is keeping up the hard work, making sure that everything in your body goes according to plan. And to understand this most amazing of nature's creations you need maths. Here are some of our favourite articles on brains, human and animal.

>It may be Sunday but that's no excuse for resting your brain. Plus has been grappling hard with the strange weirdnesses of quantum mechanics lately, and we think that you should too. So get ready to be mind-boggled.

What would Christmas be without the unlimited eating? And even though you can't taste it, there's plenty of maths in food. Here's some yummy examples.

Is maths always true?

Find some animal maths behind door number 8.

There are nearly 7 billion of us now, but how many will there be by Christmas 2111? Find out behind door number 7...

Our new postcards are too lovely to keep to ourselves! Look behind Door 6 and find out how to get your own set...

It's Cyber Monday and apparently this lunchtime we will all be shopping online. In case you are hunting for presents today, you can find our mathematical suggestions behind Door 5.

The auspicious date of 11/11/11 saw the launch of a brand new YouTube channel dedicated entirely to numbers – it's hiding behind Door 4!

Tennis anyone? Fancy football? Whatever game you are playing (or watching) this weekend, find out the maths behind our two favourite sports behind Door 3.

End of year weariness setting in? Exercise your brain and try some of our favourite puzzles – they're behind Door 2!

What do Caribbean steel drums, the London 2012 Velodrome and the quest for sustainable energy have in common? They all involve the work of engineers. Engineering provides some of the most exciting applications of maths, which impact on all our lives every day. Open Door 1 and discover the mathematics behind engineering.