What is your best attention getter when giving briefs or teaching classes?

Here is what I use for ASAP videos.
http://youtu.be/3xXDKl5OiUY

I have 2 favorites.<div>First is "self smart" and the other is the all time best opsec video.</div><div><br></div><div><br></div><div>https://www.youtube.com/watch?v=So9LshyaHd0&nbsp;<br></div><div><br></div><div>http://vimeo.com/45593328<br></div><div><br></div><div class="pta-link-card"><div class="pta-link-card-picture"><img src="http://i.vimeocdn.com/video/317143474_960.jpg"></div><div class="pta-link-card-content"><div class="pta-link-card-title"><a target="_blank" href="http://vimeo.com/45593328">SNL Desert Storm Press Conf (3 34)</a></div><div class="pta-link-card-description">Vimeo is the home for high-quality videos and the people who love them.</div></div><div style="clear:both"></div><div class="pta-box-hide"><i class="icon-remove"></i></div></div><div class="pta-link-card"><div class="pta-link-card-picture"><img src="https://i1.ytimg.com/vi/So9LshyaHd0/hqdefault.jpg"></div><div class="pta-link-card-content"><div class="pta-link-card-title"><a target="_blank" href="https://www.youtube.com/watch?v=So9LshyaHd0">self smart yourself</a></div><div class="pta-link-card-description">a prisoner explains how to self learn yourself (trailer park boys)</div></div><div style="clear:both"></div><div class="pta-box-hide"><i class="icon-remove"></i></div></div>

I liked this one...always got our attention before the briefing. :)<div><br></div><div>Office Linebacker</div><div><br></div><div>https://www.youtube.com/watch?v=RzToNo7A-94<br></div><div class="pta-link-card"><div class="pta-link-card-picture"><img src="https://i1.ytimg.com/vi/RzToNo7A-94/hqdefault.jpg"></div><div class="pta-link-card-content"><div class="pta-link-card-title"><a target="_blank" href="https://www.youtube.com/watch?v=RzToNo7A-94">Terry Tate Office Linebacker</a></div><div class="pta-link-card-description">Terry Tate Office Linebacker from the 2003 Superbowl For more Terry Tate videos check out my videos!</div></div><div style="clear:both"></div><div class="pta-box-hide"><i class="icon-remove"></i></div></div>

On the importance of a well constructed OPORD and why we should pay attention to them:
https://www.youtube.com/watch?v=LkCNJRfSZBU

It depends on the POI for the day but I always liked the way this clip motivates the Soldiers. It is shown before the long and boring International Humanitarian Law and Geneva Conventions class.
http://www.youtube.com/watch?v=FJfeD-I39CQ

I honestly think it depends on the audience. Videos, stories, etc. all depend on the audience you are talking to. A relevant story can be helpful, but through about a decade of teaching and a decade of college courses, I can tell you: the most important thing is to project that you care about the subject and and to facilitate that passion to the audience. 

I open my "Media Engagement" class with this little clip of how to NOT behave in front of a camera. Works every time ;) 

SSG Robert Burns, I've used this one with Chris Farley on more than one occasion:

http://www.youtube.com/watch?v=IvmeUStFvz8

Best line: "El Niño is spanish for....The Nińo"

Humor.  It lightens the atmosphere and brings attention.  I taught Battery II for the military license (SF-46).  Boooring!  I would give the troops a break and say "The mind can only absorb what the butt can endure."