The current quarter of CS193p (Spring 2015-16) is once again available on iTunesU.
The website you are looking at (http://cs193p.stanford.edu) was retired a couple of years ago, but evidently iTunesU folks still need it for demo code downloads, so that code (not including the Calculator demos) will be posted here (hopefully in a somewhat timely manner, but apologies in advance if we are slow).
This course is based on iOS 9 and Swift 2.2. If you are here looking for demo code and Swift 3.0 has come out, likely there will be incompatibilities that you'll have to resolve.
Please do not repost from this website on other websites--these downloads are for the individual use of those of you watching the course on iTunesU. Enjoy!