Here's how to get some nice classical music courtesy of YouTube:

1. Install the firefox extension Fast Video Download. Fast Video Download puts an icon on the bottom right of your screen that allows you to download the YouTube video when you are visiting that page. You usually have to stop the playing video, then click on it and sometimes mess around with the right click download option and back again to clicking it. It's a little finicky. But in the end you download a .flv file of the video.
2. convert the flv files into mp3 with Flv Audio Extractor. [It's a windows program, but it works on linux using wine. Just download it, right click on the file and say to run with wine. The old school command line way is to setup your wine environment with the 'winecfg' command. Then you run anything windows like this: 'wine ./.exe'. So, after installing the package, you run it like this: 'wine ~/.wine/drive_c/Program\ Files/Flv\ Audio\ Extractor/AudioExtract.exe']