Philipp Lenssen points to Mazda EarthSearch sweepstakes game. You basically download a KML file that runs on Google Earth and follow the steps from there. The game shows you hints of historic landmarks, you use your search skills to locate the landmarks on Google Earth. So far they have two steps, where you locate two different landmarks. I located both and now I await an email for next week's continuation to the game.
Optimising Digital Marketing Campaigns with Search, Social and Analytics
At SES London (9-11 Feb) you'll get an overview of the latest tools, tips, and tactics in Paid, Owned, Earned, Integrated Media and Business Intelligence to streamline your marketing campaigns in 2015. Register by 31 October to take advantage of Early Bird Rates.