I would like to put a sign up in the back window of my car (and the front window of my house) (I also want to put a "Google Does Evil" sign in my window before the cam car gets to our town, but that's another topic, LOL)

It would need to be something easy to read at a glance and only in black and white (because my colour printer cartridges cost $58 each and I'm too cheap to buy them).

So, something kinda catchy, make-you-think, easy to print out (could even pass them out, leave them lying around etc).

Any ideas, pics, concepts, links etc would be appreciated.

Thanks!
L.C.