Google Earth Competition News - Google Earth Blog - See the post for more details and examples:
First, when Google announced the release of the Ancient Rome in 3D collection, they also announced a competition for K-12 educators in the US to come up with the best lesson plan involved the Ancient Rome collection. Yesterday, Google announced six winners of this competition.
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Second, Google has announced a new competition. The new one is the Google 2009 International Student Bridge Modeling Competition. ... The competition is to build the best 3D bridge and place it in Google Earth, then submit it to the Google 3DWarehouse. And there are cash prizes including a US$5000 first prize! Read more at the competition site ...
Entries need to be sent in by June 15, noon PST. They will be judged using criteria like accuracy, low polygon count, and detail.
Here's the digital poster (PDF) for the competition.