I always love having a poke around inside an app I didn't write but it's been a while since I came across a full app that's been open sourced. This week Bartosz Ciechanowski open sourced his 3D playground app, Revolved and it's a cracker. If you're interested in a non-trivial example of GLKit, OpenGLES and integrating the whole thing with UIKit then you need to be all over this.
Brent Simmons on whether or not to use standard controls. With iOS 7 there was definitely a swing back to standard controls over the completely custom UI that we were seeing built in iOS 6 apps. Brent also posted a follow up article which is also worth a read and Greg Cox also posted about the cyclical nature of this problem.
Talking of Accessibility (we were, check the News section), I came across this blog post disguised as a gist by David Rönnqvist this week. While I have tested with Voice Over many times, I had not come across this table view "Actions" overlay before. David talks about how easy it is to break this with custom UI and the steps you need to take to ensure it is working.