i am creating a notebook for my presentation at the wolfram Technology conferenc in October and wanted to show a Youtube video in the presentation. here's what i found out: you can call a youtube video from within a notebook if you can access wi-fi where you're showing the notebook. here's an example:

SystemOpen["https://www.youtube.com/watch?v=IaO69CF5mbY"]

if you don't have wi-fi where you use the computer, you can download and save a youtube file on your computer and then just double-click on it it to run the video. see

http://www.computerhope.com/issues/ch001002.htm