If you use multiple displays, then you know that having an app or video in full-screen mode on one display nixes the ability to do anything on the other display. A fix for Youtube videos is to make the video stretch to the window's borders (and maximize the window). Here's how:

If the video link is this:


You change it to this:



The next version of OS X (Mavericks) will actually fix the full screen issue, but if you are like me and aren't planning on upgrading right away, this is a useful trick to have. Is this problem present in Windows OS's?