NoNotifications is a simple indicator for Ubuntu (Unity 7) that allows you to temporarily suppress NotifyOSD notifications. The tool is useful for presentations, when working, and so on, to prevent unwanted notifications from getting in your way or distracting you.
The NoNotifications indicator offers only two options (and Quit): "Don't disturb", which disables the notifications and changes the indicator icon to red, and "Show notifications", which you've guessed it, enables the notifications, and changes the indicator icon to green.
Ubuntu (with Unity 7) lacks a "Do Not Disturb" mode and while NoNotifications can be useful for temporarily disabling NotifyOSD notifications, it doesn't provide a complete "Do Not Disturb" mode.
A "Do not disturb" mode that also mutes the sound, disables all kinds of popups and allows scheduling when you want to activate this mode would be extremely useful. I'm not sure if the NoNotifications developer is interested in these features but nevertheless, I reported a bug for NoNotifications to include them @ Launchpad.
Install NoNotifications (NoNotifs) in Ubuntu
NoNotifications indicator is available in a PPA for Ubuntu 16.04, 15.10, 15.04 and 14.04. Add the PPA and install the indicator using the following commands:
sudo add-apt-repository ppa:vlijm/nonotifs
sudo apt update
sudo apt install nonotifs