The Two Sites I like are You tube of course and also ESPN Go. ESPN has some good outside the line segments that we have used in some of out First Aid training's in the district.
This next video is hot linked. It is from ESPN and about Concussions. Click Here.
As far as Copyright, the video was fun to watch. There was nothing new that I didn't know already. And as far as drop-box, I already have an account and use it to share stuff between coworkers and between my devices such as phone and computers.