If you activated the new Inbox Tabs then after a while you find yourself not liking them that much and would like you old priority inbox back, this is what you need to do.
If you want you can turn any Microsoft PowerPoint presentation into a video so you can play the presentation on a computer that doesn't have Microsoft Office installed.
If you are getting a vast number of email notifications sent by your Twitter account and they started to annoy you, this is how you disable and manage them.