World's most expensive stamp

The most expensive stamp in the world is about to be auctioned in New York. David Redden of Sotheby's is overseeing the sale of the British Guiana one cent magenta .

Sourdough: the pre-ferment

We make the pre-ferment assisted by "commercial home baker" Neville Chun. It's the critical final step before the big bake!

World Cup technology

The FIFA World Cup's tech highlights with Peter Griffin; from 4K TV to goal line technology and the viewing options.

Space recovery mission

A team of citizen scientists and retired space buffs is trying to bring an abandoned spacecraft back to earth more than 30 years after it was launched. With Keith Cowing is from the ISEE-3 reboot project.

Anti-social networking

The rise of the anti-social network, with Gareth Rubin.

Rice vs wheat growing

Thomas Talhelm of the University of Virginia reckons that some of the differences between Western and Eastern cultures can be explained by the crops they grow.

Bipolar disorder speech recognition app

Professor Melvin McInnis of the University of Michigan is working on a clever speech recognition app. It aims to tell when someone suffering from bipolar disorder is heading for a manic episode, just from the way they're talking.