During the London 2012 olympic games, the city of London organised several events "to see London as never seen before". One of them was a projection of images on the houses of Parliament. It was a "son et lumiere" or (light and sound show) which lasted 15 minutes and was repeated a short moment after ... here is what it looked like when seen from the opposite bank of the Thames. A new one will be repeated during the paralympics.
more informations can be found here : www.london.gov.uk/priorities/london-2012/lighting-london