Invited to this campaign through facebook. (what? … you dont have an account there?)

Blackout Britain – Lights out for the Feast of Playful Darkness, Lights out for Carbon, Lights on for Pumpkins

On a serious note, from the Campaign for Dark Skies webiste:

The amount of additional carbon dioxide pumped into the atmosphere due to inefficient UK street-lights in the last 12 months =  541,180 tonnes