On disc four of series 3, go into the scene selection, go to the last page, highlight "keep looking" and press "up." You know have the whole easter egg that was part of the story.
Doctor Who (2005) - 1 easter egg
Easter eggs are hidden bits on DVDs which aren't advertised on the cover, but if you know where to look can provide all sorts of fun extras.
Across whole show
On disc four of series 3, go into the scene selection, go to the last page, highlight "keep looking" and press "up." You know have the whole easter egg that was part of the story.