Have you ever visited Google’s Home Page on your birthday? You will be pleasantly surprised to see a “Happy Birthday Doodle” just for you on the homepage. It happens to be my birthday today, I know, April Fool’s Day, and I was really happy to see this.
You would also see the same image in Google Now on your Android phone. Isn’t it interesting? Only condition for you to see this is to be logged into Chrome while browsing and obviously Google knowing that it is your birthday. Don’t believe, Google knows it all – someone (if not you) must tell Google. :)