Javier Soto with another take on Core Graphics drawing into cached UIImages that was mentioned last week. This super clean class renders drawing code into an image on a GCD queue and caches the result.
Automatic creation of RESTful web services by pushing up some Objective-C code into the cloud? Interesting idea. Who said Objective-C wasn't suitable for server side code?
Mark Granoff on tracking down a subtle mistake while implementing protocol methods. It's always surprising to me how many people don't know about the "-", "space" feature of code completion which means you don't need to enter the return type of a method to have it complete on known methods.