For the last month or so, the Google home page has played with the famous colored-letter logo by morphing it into a sci-fi in-joke and later adding another "l" to indicate the company's 11th birthday.Now, a portrait of Mahatma Gandhi--the Indian leader whose 140th birthday anniversary is today--has become the "G" in the logo. Yes, indeed, his head of the man known as "The Father of a Nation" is a letter.