The act of throwing a window out of a window.

Not a useful thing to do by any stretch of the imagination, except if you are a performance artist. If you are a performance artist, then for you, meta-defenestration becomes a powerful tool, symbolizing...
um, symbolizing...
think, c'mon...
well, it should be obvious what it symbolizes.

Woundweavr : You're full of crap. But wonderfully so. ;)