Boy, this is exactly the kind of thing I want floating around in my neighborhood - especially after the local hackers get at it :)
Urballoon -- an "urban media space" wherein a balloon hovers three stories in the air, equipped with a projector and a wireless connection. The balloon / projector is used to "broadcast" images or text sent to it via a website onto the ground below. Anyone can hop on the page and create a message for the balloon, so we'll assume they have very good profanity filters.
I have enough stuff I don't want in my inbox - I don't need it outdoors, too :)