Don't need to download. watch it. its automaticly download and save to your harddrive.

All you need to do is watch your video, it automatically download it, not only youtube videos but also download protected, watched only videos.
If you watch a video in the Internet you just downloads it, when you watched a picture in the Internet you just downloads it, your browser downloads it to a random hidden temporary folder and show it throw your Internet browser (fire fox, opera, Google chrome, Internet explorer) no matter it is a protected one or downloadable one, This is the one and only way to brows the Internet.It just download it and show it through your browser. and when you go to the next page or close the browser it deletes the content in the temporary folder, but browser ant give to save the video it just even not tell where your temporary folder is, ( probably its in your main driver)

I use a software called "Freecorder" to change the video temporary folder to my custom one..
you can download the software in here. works for Internet Explorer ,Fire Fox ,Opera ,Google chrome (not tested in safari but i bet it works)

watch a video, click "freecorder video history.exe", you have your watched video. or you can change temporary video folder by run "freecorder setting.exe"