ReCordMyDeskTop

recordmydesktop is a program that allows you to take a video from your desktop. In practice, you often want to record a window only. To do this, start recordmydesktop like this:

recordmydesktop --windowid $(xwininfo | grep "Window id" | awk '{print $4;}')

A cross will appear. Aim it at the window you want to record and click. Then the recording will start.