In this example project we show various aspects of the new UI system in Unity 4.6.
Examples include:

UI aligned in 3D with perspective.

UI lit by light sources.

Scripts for handling drag-and-drop and for moving and resizing a window.

Placing a RenderTexture in the UI.

A scene demonstrating the built-in auto layout components, including a grid and nested layout groups.

A scene showcasing the default built-in controls such as buttons, toggles, an input field and a scroll view.