Festo - SmartBird

The first comment is 'Da Vinci will be proud' - indeed!!

CityVille

CityVille, a Facebook app from Zynga, has grown from 0 to 90 million in just about a month. Mind is blown!
Source: http://kevinrose.com/blogg/2011/1/11/cityvilles-viral-growth-hooks-levels-1-3-deconstructed.html