If you are (as I am) annoyed by the default setting of Sunday as first day of the week, there’s an easy fix for that. Following will set Monday as first day of the week on your gnome-based system.

Solution

Just edit your ~/.profile file and add this line:
export LC_TIME="en_GB.utf8"

After that, you would have to restart your Gnome session. Either you log out and then log back in again or type this in your terminal:
sudo killall gnome-session

Monday as first day of the week