To download video from YouTube, drag the bookmarklet below to your bookmarks toolbar. You can then click on it whenever you are visiting a YouTube video URL to download the FLV video featured on that page.
This was made possible by ctrl-c.org YouTube API. I put together the bookmarklet because Adobe’s 32 bit Flash plugin is usually not very happy in a 64 bit environment on GNU/Linux. Now I can watch everything fullscreen in MPlayer.