A screencast is a digital recording of your computer desktop. This is helpful for when creating tutorial and instructional materials, demonstrate how to reproduce a bug, and demonstrating the latest desktop software.
Kazam is an easy to use application for recording on-screen action.
Recordmydesktop captures audio and video data of a Linux desktop session.
istanbul (Trusty and below only)
Istanbul is a desktop session recorder producing Ogg Theora video.
* Ubuntu Desktop Guide on Screenshots and screencasts