This is a youtube downloader that works (it does use the old and invalid http://youtube.com/get_video url).

==Install==
sudo gem install youtube_utils

==Usage==

To use it as a command line tool:
youtube_utils <youtube_url>
For example:
$youtube_utils http://www.youtube.com/watch?v=cRdxXPV9GNQ

To use it in your code:
requires 'youtube_utils'
YoutubeUtils.new.get_videos 'http://www.youtube.com/watch?v=cRdxXPV9GNQ'

YoutubeUtils#get_videos will return a list videos along with their url/type/quality. You can NOT run it on the server and give the urls to someone else. The url is only valid for machines that execute YoutubeUtils#get_videos method (youtube generates an unique url for each computer). 

==License==
Copyright 2011 Intridea Inc ( http://intridea.com ), released under the MIT license.