Guess what? It doesn't work. At least, not the way Martha says it does. As-is, the tutorial basically leads to paint on paper that will sort of scratch off, but will also take off part of the paper with it. Not good. But, thanks to other who have done some trial-and-error with the project, we learned that if you put some kind of gloss surface - like tape or contact paper - under the paint, it works like a charm! After running around like crazy trying to find little round glossy stickers with no luck we ended up laminating the entire project and painting our scratch-off circles over that. Perfection!!
Although I am apparently suddenly sick, I'm excited for the party this evening and can't wait to hear people's reactions to the scratch off tickets we left on their chairs bright and early this morning. And, I'm excited to add another project to my "saw it on Pinterest and actually tried it" list!