I also like it when a game uses hardware’s new features in surprising ways.
Something thing that blew my socks off: I recently bought a Nintendo DS and Zelda’s Phantom Hourglass with it. Quite early in the game I was stuck with getting into a castle. There were two candles in front of the door and the hint was that I had to blow them out. I had been searching the entire island for ways to do so, maybe bellows or a bag of wind (this is Zelda after all) but I couldn’t find any of those. I almost gave up and then remembered that the DS also had a microphone built in. So I just blew on it, and what do you know, the candles went out and the door opened.
Later, in the same game, I found two parts of a treasure map. They obviously fit together but there was no way you could do so. Until you realise that you can drag one piece of the map to the top screen, the other to the bottom, close the DS shut, and so imprint a mirror image of the top map onto the bottom
Pure genius.