Black out the screen except active window

this may not be what you are looking for, but:
- option command D to hide dock
- option command H to hide all windows except active window
- and a black background, and all you have is the menu bar and the active window (although if you have multiple windows of the same application they will still be visable)

 

What are you using to view the videos?

In Quicktime X you can watch videos in actual size but full screen, thus resulting in a little video on a big black screen.

EDIT: iTunes also provides this option.

 

Could you display it at actual or double size then do a screen zoom (control-scroll)?

 

There's also a free app for this called 'Think' -

http://freeverse.com/mac/product/?id=7013


seems like what you were looking for, and can be used for any app to completely banish any distractions on screen...

Coops

 

if its to watch video in full screen just hit 'cmd f' this expands the size to full screen no title bars and black borders for different sized formats.. easy!