Unidentified guys found a vulnerability on the Apple site and
used it to advertise Windows 7:

With the help of simple substitutions in the URL, you can "put" on this page of the site any image with any text. There are already thousands of
posts on Twitter on this topic.
I wonder how soon it will be noticed in the apple company? :)
UPDATE: "Hole" promptly covered :)
UPDATE2: The hole was covered, but not in every language version of the site.