On Google, search for [Bletchley Park] and then watch the right hand knowledge graph box decipher the code to spell out Bletchley Park. That is the latest Google Easter Egg on their search results.
Here is a picture of it in action:
Here is a video:
Bletchley Park was the central site of the United Kingdom's Government Code and Cypher School, which was known for during the Second World War to break the secret secret communications codes of the Germans and their allies.
Kristian Köhntopp from Berlin posted about this on Google+.
Forum discussion at Google+.