On October 8, 2008 I gave a presentation at the New York City iPhone Developer Meetup on using Core Animation to design games. Specifically, the talk was focused on creating a scene using CALayer and then responding to touch events so that certain layers can be dragged around the screen.
Download (3.2 MB) the Xcode project and slides.
In my presentation I make reference to Apple's GeekGameBoard sample. Jens Alfke has posted an iPhone version on his blog.