Youtube-dl
Somebody asked me how to download youtube videos using the command line. This post is her answer or to anyone who doesn't want to use the proprietary Flash plugin (A replacement for flash is Gnash,a free and opensource flash player, which is, I think, better the Flash), for security or ideological reasons.  Another reason may be you are bandwidth impaired like me or just want to watch youtube videos at your own leisure. Youtube-dl also works in Windows: follow this link for further information, The following instructions has been tested in Linux but could easily be applied to the MacOS or any Unix-like operating system.
You will only need Python 2.4 or greater installed to run the script, which is included by default in most Linux distributions.

First you need to install the script. Download the latest tarball from
http://bitbucket.org/rg3/youtube-dl/get/tip.tar.gz. 
you could use wget by typing in a terminal:

then extract the file by typing
tar xvf tip.tar.gz
then change directory
cd youtube-dl
And to download a video:
copy the youtube URL, in this example Great Guitarists of the World
then paste the URL to your terminal with the command:
or you could use the -o switch for your own custom title so that you wont end up with meaningless strings
./youtube-dl -o Turkey.flv http://www.youtube.com/watch?v=qm5XPAOvzwg
Then simply use an appropriate media player that handles .FLV files like vlc or mplayer
Go to the this site for more information and tips.

Enjoy!