As a rule, You Tube videos are not meant to be downloaded. If you search around on the Internet you can find ideas on how to do so, though I'm not sure what the legality of doing so is.
“The tragedy of life is not that it ends so soon, but that we wait so long to begin it.”- W. M. Lewis
“It takes a lot of courage to release the familiar and seemingly secure, to embrace the new. But there is no real security in what is no longer meaningful. There is more security in the adventurous and exciting, for in movement there is life, and in change there is power.”- Alan Cohen