Today is Labor Day in the U.S. and it is also Freddie Mercury's birthday. Freddie Mercury is well known as the lead signer of Queen.
He was born today in 1946 and died from bronchopneumonia brought on by AIDS on November, 24 1991. He is one of the most well known singers of the era and has been very influential in HIV awareness.
That being said, Google has a special logo for him on almost all properties except Google.com, because Google.com is remembering Labor Day. Google said they will show the logo on September 6th, tomorrow on Google US instead.
Here is a static picture of the logo and a video below:
On Google.com today is a small American flag for Labor Day:
Bing also has a theme for Labor Day:
We also have a Labor day theme here as well, it is a bit more festive:
For last year's Labor Day logos, see this post.
Forum discussion at Google Blogoscoped Forums, Google Web Search Help.