Using safari 4.0 or above open a website with some flash content or an embedded video etc,
As an example i'll use (sess.net).
Open the page with the desired content in it,
Go to the "Window" menu and select activity, by now safari should have started to open the content.
Once there it will open a window called activity and show you a list of websites you are currently on.
Choose the appropriate one, in our example that would be (sess.net finger lickin good).
Then from the drop-down choose the file in question
-At this point its obvious in most cases we'll be looking for something along the lines of the file name or anything above lets say 1-2mB,
Double click that line and it will open in a new window,
-Now you have two choices, either the file will automatically be opened in which case you just copy the link to any download manager,
Or,
Safari will ask you if you want to save the file in question.
This method works on various websites such as youtube, Sess, etc.
I have come across some websites that for some obscure reason still manage to hide the content somehow, but for the most part this method will work.