Cool tip discovered just now whilst watching a video podcast in iTunes.
The overlay controller that shows up when you mouse over a movie window, like this,
can be moved by clicking in one of the non-control areas and dragging. Handy for when there’s info being obscured, but you’d like to keep the controls active, such as this,
I’m probably the last in a long line of people who already knew this, but just in case. :)