I like to download lectures and presentations from YouTube so that I can play them back using VLC at 2x playback speed.
My favorite option for downloading is this YouTube video download GreaseMonkey script that adds a download button to the YouTube video page. It works in Chrome, and in Firefox with GreaseMonkey. This is vastly superior to the more-popular YouTube video save sites that require to you execute a sketchy Java applet.
Follow this link to find a way to download youtube videos
http://www.youtube.com/watch?v=9UyozaXyPds
Definitely have to be careful. Some of those downloaders are sketch! I do find the torch browser to work well without anything weird going on, but it’s always good to have a few methods. Thanks for the tip!