Reeder is a rss reading application for the iPhone. It integrates with various RSS services, such as the now defunct Google reader and Feedly.
I choose to feature Reeder as my App of the Week because the navigation is very well designed. It has been carefully constructed to stay out of your way when reading. Below is a gesture guide from the ReederApp.com website.
As you can see the focus is on gestures instead of icons. To maintain visual sense of the gestures, Reeder takes the user through a very clear left -> right path. This enables you to navigate around by sliding from the sides of the screen.
The only other major gesture is pulling past the bottom of the text to get to the next entry.
Additionally, there are two other pull from the right side gestures which revel a very nice social integration and a mark-as-read action.
Other than their documentation, all of these gestures can be discovered and are hinted at through animation when the actual interface icons are clicked.