Today if you visit the Google home page in Google USA, you will see a logo that shows Martin Luther King giving his "I Have a Dream" speech. Today is the 50th anniversary from the day that Martin Luther King gave the address at the March on Washington on August 28, 1963.
To make sure all Americans remember, Google has a special logo, aka Google Doodle, showcasing the event.
Here is a video of the historic speech by Martin Luther King named "I Have A Dream":
To learn more about the day, the speech and the man, see Wikipedia.
Google has always had a Google Doodle on Martin Luther King's birthday and to see all those MLK Doodles, go to this page. Today is not his birthday, but the anniversary of the "I have a dream" speech.
Forum discussion at Google Web Search Help.