I've stuck them in the windshield of a few cars I've come across that have those brain-dead "COEXIST" bumper stickers.
Note: I wouldn't print very many with an ink jet printer, it will use a lot of ink. I'll probably try to use Photoshop or similar to invert the colors if I run out of the dozen or so I printed.
You should be able to paste it into Word and change the font color from white to something dark and change the setting to avoid background color printing.