"Outdoor digital projection in urban environments is a great method for getting your content up big before the eyes and in the minds of your fellow city inhabitants. This tutorial comes out of trial and error and it works. But please be careful. Helpful comments on safety and alternative methods are encouraged. The majority of this tutorial is aimed toward using a 2500 lumen projector (or smaller), if you have access to something more powerful you might want to skip straight to step 6." via instructables