See how Derren Brown used the Wisdom of Crowds to predict the six winning numbers in the National Lottery.
Starts from 7:00 here with Francis Galton and the weight of an ox getting another airing:
Derren Brown Lottery Prediction (Part 3)
Here is a great illustration of the seer-sucker theory in operation courtesy of Derren Brown:
Derren Brown - The System (Full)