Easter Egg in Google Books Ngram Viewer

Rickrolling seems to be Google's favorite prank. If you try to search for [never gonna give you up] in Google's recently launched Ngram viewer, you'll have a pleasant surprise: a YouTube video of Rick Astley's "Never Gonna Give You Up".

Never gonna give you up,
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry,
Never gonna say goodbye
Never gonna tell a lie and hurt you...

{ Thanks, Federico. }