On the edit post / page screen if you compare two revisions, which are the same you get presented with a black screen and a message about infinite loops.
Obviously comparing the same revision to itself is pointless, but this 'humorous' Easter egg wasn't so funny for my panicked, non-technical client.
Given the clarity of thought on the rest of the WordPress UI this was a little disappointing to discover.
Anyone else like to see this removed?
To see the easter egg in action: