This is a beautiful custom collection view layout by Niels de Hoog. I recently made a layout similar to this but it had a ragged end to it (which didn't matter too much as it was (virtually) infinite scrolling. This is a much better approach than I used as it guarantees a square edge to the end of the layout. It's an implementation of "The Partition Problem" translated into Objective-C and it works beautifully.
Following last week's open source release of Inkpad, this week sees Steve Sprang also open source his Inkpad's more famous brother, Brushes. Back in 2009 this app was used by Jorge Colombo to draw cover images for the New Yorker. This is a great slice of history, I wonder what he will release next week.
How about a swipe out "drawer" view controller with all the playfulness of UI Dynamics integrated right into it to give it that iOS 7 shine? Well Eric Horacek has released a library this week which does exactly that. It looks to be well documented and written for a general use case rather than to fix a specific problem which makes it worth a look.