Hidden for three decades in a landfill deep in the New Mexico desert lie thousands of Atari cartridges of what is widely believed to be worst video game made - or so the urban legend goes.

A group of film-makers hope to get to the bottom of the mystery this weekend by digging up the concrete-covered site in search of up to a million discarded copies of ET The Extra-Terrestrial that the game's maker wanted to hide forever. The game and its contribution to the demise of Atari have been the source of fascination for video game enthusiasts for 30 years.