S is for Sustainability. Sustainability is very much part of the ethos of Greenbelt, the festival of arts, music and social justice, that takes place each August Bank Holiday weekend in the grounds of Boughton House near Kettering, Northants, in the UK. So it's a good time to point you towards their latest blog entry, with its details of their Green Cup recycling scheme. Rather than end the festival with tons of used plastic glasses and cups thrown into landfill, festival-goers are being encouraged to pay a £1 deposit on their own cup at the start of the weekend, which they can keep and reuse. They then have the choice to either return it and have their deposit refunded, or keep it as a souvenir.