End of year weariness setting in? Revive your brain with some of our favourite puzzles, as chosen by our readers and the *Plus* team!

Bid farewell to 2011 with this puzzle from *Plus* reader, Paulo Ferro.

*Plus* reader Aziz Inan has a question for you: Which mathematician is in their prime?

Think you know how to use the numbers 1 to 9? Our colleague James Grime puts your digits to the test.

Try your hand at a puzzle from the *Hands-on risk and probability road show*: How many socks do you need to grab to find a pair?

Buster the cosmic rabbit is playing ball with the Earth and very large piece of string... A slightly surreal take on a favourite puzzle with a very surprising answer!