[H] Saving YouTube Videos

[Anthony Q. Martin]

Is there a way to save to hard drive a YouTube video that plays inside a 
browser on some webpage?

I'm building up a powerpoint presentation and I'm not sure I can count 
on internet access at the location where I will present the 
presentation...hence, I'd live to have it play from my HD.

I can't seem to find any way to save those videos.  I can copy/save 
images easily, but not video.  What gives? Some kind of protection?