We had our library's first public demonstration of 3D printing last Thursday and it was a resounding success. We had at least 30 people show up with oh so many questions.
The demonstration consisted mostly of me printing one of the example/test prints and giving a play by play of what was happening all while explaining the names of the various bits of the machine and how it all worked. We also had a camera and a projector so we could show everyone what was going on up close by zooming in with the camera and projecting its view onto the wall. We gave out free sample objects and we passed around several example objects showing different textures and different print qualities. I had about 50 photos showing some of the various objects we've printed including a few objects designed by students in the workshop we've been running as part of a grant these last few months.
This is a great idea! I'm going to steal some of this for my Makerspace. We've been wanting to put a camera on our RepRap Mendelmax (it's yellow rails and black parts we 3d printed, so we call it "Bumblebee").
I am not surprised but am so glad this worked out for you.