Google and Sony Pictures have partnered to promote "The Da Vinci Code," with Google releasing one Da Vinci Code-related puzzle or riddle on users' personalized homepages each day, through May 11, with the last puzzle for contest finalists on May 19, the film's release date, reports CNET. The move is a significant departure for Google: It's the first time that it has done a cross-promotion with the film industry - and it's "the first time…Google is giving marketers access to its formerly sacrosanct home page - well at least the personalized version," as MicroPersuasion's Steve Rubel pointed out last week.

"This is really something new for us and we're looking to do maybe a handful of these a year," Dylan Casey, brand and entertainment manager for Google, told ClickZ. "It's something we're interested in pursuing to see how we can interact with our users and get some feedback as to how Google works as a platform for these types of initiatives."

Agency Big Spaceship worked with Google and Sony on the look and feel of the puzzles and microsite elements.

Participants can enter the contest through the "Da Vinci Code Quest on Google" site, or via Google; they must have a Gmail account and Google Homepage. Each new puzzle will be directly linked to the homepage each day at 1pm EDT, giving new users a reason to visit the page daily.

Once solved, each puzzle introduces a riddle that calls for the player to use Google Search, Google Maps, Google SMS or Google Video. The first 10,000 people who complete all 24 puzzles will be invited to participate in a final 48-hour challenge. The grand prize winner will receive vacations to New York, Paris, London and Rome.