The major search engines are remembering 9/11 today on the tragedy's 11th anniversary. Google has not put together an elaborate doodle or anything (they usually stick to more upbeat events for that), but is displaying a tasteful black ribbon underneath the search box.
Bing has a much more visual display:
Frankly, the image above doesn't really do it justice. If you go to the site, you can see the water moving and whatnot.
Yahoo is simply displaying a related story as its main news story:
Ask is displaying a September 11th Memorial trivia question:
There don't appear to be any changes to the homepages of alternative search engines Blekko or DuckDuckGo.