Links: Santa Tracker Popular, Volvo Ocean Race, Lost World Discovered, Cold War KML - Google Earth Blog - I'm including the GEB post for this prize-related portion:
Volvo Ocean Race - The official site of the Volvo Ocean Race (a round-the-world sailboat race with multi-person crews in 70 mono-hulls capable of 30 knot speeds), has released a Google Earth file that lets you track the boats as they complete their journey. The GE Volvo Race tracker includes placemarks with links to pictures, stories, and videos.
The Google Earth Blog has a lot of other recent posts worth checking out: World Sunlight Map, New 3D Cities, Alps Ski Information Layer, The Year 2008, and New Improved Ancient Rome 3D. I'll just provide the links to those Google Earth innovations without further comment since I don't see any prize connections there. They're just cool is all.