Today is a day to thank our troops for their bravery and all they have done for this country. As a way to thank our troops, Google, DogPile, Live.com and the Search Engine Roundtable have put together logos and themes for the day. I personally do not currently see a special logo or theme from Yahoo or Ask.com, which is unusual.
Update: Google left out coast guard so they updated the logo:
Forum discussion at Search Engine Roundtable Forums.