Pop Down Project

The Pop_Down Project offers an alternative to the “pop up” advertising we encounter on the streets. They write:
"On the Internet, getting rid of unsolicited pop-ups is pretty easy. In real life, things are a tad more complicated. The Pop_Down Project aims at symbolically restoring everyone’s right to non-exposure: Just stick a “Close window” button on any public space pollution."


Apparently you can head to the site to download the template and start sticking yourself. It's kind of fun, but I wouldn't be so sure of its effectiveness.

Sources:
Urban Prankster
Pop Down Project