This may be the first year that Google linked their Google Independence Day Logo, aka July 4th Doodle, to a search result for [When is Independence Day?], which shows off the Google Now like card answer. If you didn't know, Independence Day in the United States Of America is today - July 4th.
Like every July 4th, Google and many other search engines have special logos for the day.
Google's logo is animated and has you go through a road trip of America, with snap shots of pictures of that road trip. Below is a video of the logo and a static image.
No logo from Yahoo, which should not surprise people by now.
Happy Independence Day, also known as July 4th! ;-)
Forum discussion at Google Web Search Help.