Some clips on YouTube have a cool feature called "Turn lights down". This is an example of how it can be implemented using jQuery. When you click on "Turn off the lights" link, shadow covers entire page, except the movie and the link (which changes to "Turn on the lights").
I think it's very simple, don't you?
Ah, and yes - this works only if you listen to this song while cliking ;)
Some other songs from Metallica:
> Fuel
> Fade to Black
> The Unforgiven II
> Fade to Black
> Until It Sleeps