mcPKG is the project I worked on last year. It is written in Objective-C.
The purpose of this app was to communicate with JotForm API to retrieve user submission / files and then generate a control file that later on would be used to create UNIX executables. It uses Core Data to keep local database in sync with servers.
In addition to using JotForm APIs, this app also utilizes Parse API to separately store user data (user registration processed from JotForm). It uses Facebook SDK, AFNetworking, MagicalRecord, etc.
This project also demonstrates a good understanding on REGEX for input validation. It can also be used as an example of how to process HTML files into foundation objects.
All-in-all, this project took me a couple of month to draft and complete. It was insanely fun to implement. It is 100% functional given the right API keys and URLs.