In the context of Christmas and the the presents I got for my nieces I was reminded of scratch pads, something that I have had on my "to try list" for a long while. Often seen mostly as a children's toy, I think that that they allow for some interesting projects. They can also be combined with some coloring so you get both, color and the holographic effect of those scratch pads. Of course the scan of the holographic paper only gives a static image, but in moving light it looks quite interesting.
I plan to offer a scratch pad workshop at the next brony meetup in Cologne, so the first scratch image I came up with shows our meetup's mascot Colonia.