Making youtubes interactive

Using youtube's annotations app you can add text and links to video. You need a) a youtube account and b) to upload the video into your account (ie use your own videos or upload ones you've downloaded). And then: in your account open ´My videos´ and the dropdown menu besides whichever audiovisual delight you wish to teflise:

More info on how to do it:
here and here
A couple of examples of how it could be exploited in class
Magic trick
Choose your own adventure