Downloads most YouTube videos, but you have to refresh the page every time or it won't work correctly. I tried this with a playlist I have & it only worked if I opened the next song in a new tab or refreshed the page in my current tab. I only extract the audio from music videos for my own personal use, so I believe this would be considered as fair use, which YouTube seems to allow. This is also the only one I know of that works on YouTube right now... kudos to the author. :D