This article explains how to move a primary (root) partition to an extended partition. There are several ways this task can be performed; however, I chose to keep my system generally intact, introduce minimal changes, and use no external storage (other than a SD card for the LiveCD).
I had a disk layout as follows:
Resizing partitions is often a necessary task with any computer. The need may arise for a variety of reasons, from adding or moving disks to shrinking less used partitions and growing more frequently used partitions. Luckily, several commonly available tools (gparted and/or partition magic) make this task easy, even with a complicated disk layout.