I sure do agree with the topics that everyone has suggested. Sometimes people would love a simple block to make. Anything that demonstrates how to get the most from our scraps would be valuable. Strip piecing? When I learned the strip tube with the 4-2 1/2" strips, I thought I had to have a special ruler, only to find out from tutorials and the members here on the board that a regular square ruler with the 45º line would work just fine. Saved me some bucks. I also agree with mitering, too. I spent the day sewing with a lady who had been sewing for years,didn't now how to miter her corners. It was empowering to me to be able to show her and make something that seemed hard, very simple and easy. Good luck with your event, hopefully you can enlist the help of others to help you.