From Alessandro's Wiki
save a video
- the flash player uses /tmp to store temporarily video files, you can open a youtube video on the browser and then go to /tmp and save the file called FlashXXXX on your resources.
- on mac, the temporarily flash video files are located in /private/var/folders/X7/X7CrrB7gG2qV0GdYDHCLYE+++TI/TemporaryItems
X7/X7CrrB7gG2qV0GdYDHCLYE+++T will be different on every user account
- google it, I don't wanna know