But the One Million Masterpiece is different. For a start it's for charity (charities, plural to be precise: Oxfam, Save the Children, Action Aid, World Cancer Research Fund, WWF) and secondly it has absolutely nothing to do with advertising.

Here's what you do: sign up to the website and make your donation (minimum of £3.50) which buys you a 5cm x 5cm share of virtual canvas to do with what you will. Drawing tools are provided so you can doodle away to your heart's content, and you can even see the where you tile will end up and the surrounding works so if you want to be all clever and contextual there's nothing to stop you.

And once this giant, international community art project is finished they're going to print the whole thing off (let's hope they have a few spare cartridges) and display it in London next year. So no naked portraits of yourself ok, there's a good chance your mum might see this.