I was watching some clip in youtube. And a few seconds later I saw a new item in my downloads folder and it was the video in mp4. Any idea how I did it? I can't replicate it 
Oh I do use click to flash. But I only clicked to play the vid. Maybe double clicking it downloads it?
I just tried and it didn't work with double click. And I had to see the beginning of that stupid prom makeup video tutorial. Bwah.
Maybe it was some kind of shortcut?
I download my youtube videos through safari by going to Window, and underneath downloads theres "activity". I click that, and then I download the biggest file on the list, under the youtube page I'm on.