"jParallax turns a selected element into a 'window', or viewport, and all its children into absolutely positioned layers that can be seen through the viewport. These layers move in response to the mouse, and, depending on their dimensions (and options for layer initialisation), they move by different amounts, in a parallaxy kind of way."
Voilà un joli site qui exploite subtilement un effet de parallaxe vertical, pour donner de la profondeur à la page, astucieux !
L'outil de visualisation lié à Facebook ou Twitter, fizz, est plutôt pas mal, pour compléter.