I've published a game that I've worked for the lasts months through AppStore.
It's name is Crazy Twirl Game (http://games.alessandrosilva.com/crazytwirl.html
It is a accelerometer based game. You control a projectile and need to avoid some obstacles.
The Game control is a bit hard to get, but it is good for play, and requires accuracy and speed to turn the device while you move through the scene objects.
I've posted a video in youtube with me playing the first stage (http://www.youtube.com/watch?v=AGRR_DUamkM
To get a better feeling about the gameplay, it is necessary to hold the device as a car steering wheel.
As you can see, the game uses lines to show the graphic assets, I thought it was the best thing to do, because I can use a lot of software to create the content (blender, inkscape, etc...) and the rendering code isn't complex.
Recently I've posted some details about the implementation I've done. As well as I have a open library, I plan to make a good doc about some parts of the framework and open it with the original library I have.
The link to the tech post: http://alessandrosilva.com/index.php?option=com_content&view=article&id=69:crazy-twirl-game&catid=36:development&Itemid=58