While discussing my previous post containing the YouTube videos for the full version of When Dinosaurs Ruled the Earth one kind reader referred me to the VDownloader website. Looks like there is now a free software application available that allows you to transfer your favourite YouTube videos (as well as a couple of other formats) into the more universally acknowledged AVI or MPG formats.
Methinks that is indeed something worth checking out. After all one never knows how long some of your favourite YouTube videos will remain there. ;-)