Be seen! This will teach you how to make a giant sign that can be seen at night. We will be modifying an old-school overhead projector and using a large wall as the screen. The effect is amazingly professional looking, but the entire project cost only $30. I built this to help a friend promote her company. Almost immediately after using the Night Billboard, she noticed an increase in business. I am planning on building another one that I will lease out to people wanting to advertise on it. In my town (NYC), even a small ad on a telephone booth can cost $20,000, so I expect that I should be able to make at least a couple grand a month leasing out space on this sign. In any case, I've tried to be very specific about the parts I used and the necessary modifications. If you build a Night Billboard, feel free to post pictures here ... I'd love to see them!
http://www.instructables.com/id/Night-Billboard/