There is an even easier way, and this worked for every single site I've been to. Just copy the video from cache

.
First go to the web page of the video you want to load, and watch the bar until the video has been fully downloaded. Now Minimize, DO NOT CLOSE, and navigate to the /tmp/ folder. In there you will find many video's labeled
Flash123dsasd12
it starts with flash and has a bunch of characters. Open up mplayer, or any other player that can play flv files, and drag in each flashXXXX file until you find the one that is your video. copy the file out of /tmp to your home directory. convert or just watch it like that.
Here are the steps again
1) Open page with video, wait until it has fully loaded
NOTE: do not close tab or window
2) Navigate to /tmp/
3) Play all video labeled "flashXXXXX"
5) Copy flashXXXX file to somewhere else
6)???
7) Profit