Projector: Image-Based Area Lamp

I’ve been reading some tutorials online trying to figure this out, but no one seems to be able to provide me an answer. I’m trying to get an area lamp to project an image onto whatever I point it towards. Here’s an example of one of the tutorials:

If anyone can figure out how to put together a simple textured lamp, it would be greatly appreciated. Also, what would be the best material to project onto? It might just be the diffuse shader I’m using on the plane I’m projecting it on…

Edit: After messing around some more, I was able to get it to show up with a glossy shader, but this didn’t work as it wasn’t the lamp being projected onto a surface. I was just reflecting a textured surface. I hope that makes it more clear as to what I’m aiming for here.