A new feature in InDesign CS6 is the Content Conveyor that lets you collect elements from a layout and reuse them quickly and easily. Unlike a library that must be created in advance and then opened within your layout, the Content Conveyor lets you collect elements as you go along. It represents a more spontaneous, on-the-fly way to work with design elements that will be reused and repurposed. Think of it as copy-and-paste on steroids.
CreativePro has a great walk-through of the Content Conveyer. At first I didn’t understand how it would fit into my workflow, but after using it a few times, I’ve found it to be quite handy.
You can read more about it here.