CouchDB style local NoSQL database from Jens Alfke using SQLite for underlying storage. Can be used purely for local storage or but also supports replication to CouchDB instances. There is a demo app available as well if you want to have a play.
Nick Bona with an interesting blog post about creating a custom UIActivity. The implementation here is obviously quite specific to SoundCloud but you might find it an interesting code sample if you are thinking of implementing your own UIActivity subclass.
Interesting idea from David Keegan to use a tool like PaintCode to generate drawing code which is then cached to bitmaps at runtime in an attempt to try and reduce the ever increasing size of our app bundles (amongst other things) while retaining efficient rendering.
Ever struggled with testing your networking in an app? This newly release library from Luis Solano, Nocilla is a very clean library for stubbing HTTP requests in your unit tests. Problem solved.