Microsoft Japan implemented a very unique idea for online ads. There was a almost similiar ad coke made, i will put that here as soon as i get to see it again.
Only drawback is it only work with IE, I tried to playaround with it on opera and firefox but it seems like developer has to do some more brainstroming.
hint : slowly scroll down the page and then scroll up.
Agency: HAKUHODO, Tokyo
Creative Director: Hideaki Sakuma
Designer: Kuroda
Programer: Taishi Izumikawa