Pie Progress is a type of circular progress view similar to the one that you can find in iOS devices while updating applications. It's a simple to use library where the progress gets updated by passing values to a single method.
This library provides an easy to use API for switching between fragments that share the same container. Implementing tabs, such as the ones Instagram has at the bottom of the layout, is a much simpler goal to achieve when using TabController.
Tabs can be switched by using either show/hide or attach/detach. You can even provide your own implementation of the way tabs are being shown.
TwitterCover is a parallax top view with real time blur effect.