Turns Do Not Disturb on or off, with notifications.
If you're using the workflow in languages other than English, edit the two Applescripts and change "Notification" to the appropriate version in your language. For example, in Spanish, change "Notification" to "Notificacion". This word refers to a UI Element in the MacOS Notification Center.
Adapted and embellished from Ender's workflow: http://www.alfredforum.com/topic/5266-toggle-do-not-disturb-w-yosemite-support/ Borrowed applescript from ialexryan's comment here https://gist.github.com/Zettt/fd9979100d4603e548d6