You may or may not be aware of Google’s subtle attempt to promote national holidays , specific anniversaries, and birthdays of historic people, inventions, and events. Every so often when you visit Google.com, they change there logo on the front of their website for an entire day to celebrate something. Some of the most recent logos have been, Invention of the Bar Code (Oct 7, 2009), Mahatma Gandhi's Birthday (Oct 2, 2009), Crop Circles (Sep 15, 2009), Comic-Con Conference (July 23, 2009), and the 40th anniversary of the moon landing (Jul 20, 2009).