recordeMyDesktop

Makes videos out of your desktop.

Capable of generating only ogv container, not mkv.

Comes in both command line, and GUI versions. The GUI does not add much, so stick to the CLI.

Most useful command:

alias rmd='sleep2 && paplay ~/share/sounds/alert.ogg && recordmydesktop --stop-shortcut Control+Mod1+z'

start recording in 2 seconds
play a sound before it starts
stop on Ctrl + C on terminal or Control + Alt + Z from any window. Rationale: easy to press with a single hand.
save output to out.ogv, out-1.ogv, ...

Use if from a drop-down terminal like Guake so in the 2 seconds you can make it disappear.

Global shortcuts: http://askubuntu.com/questions/200952/what-is-a-desktop-recorder-with-global-shortcuts

Screen area selection: http://askubuntu.com/questions/156606/how-can-i-accurately-select-an-area-of-screen-to-record-when-using-recordmydeskt