Any grown-up Girl Scouts out there remember Sit-Upons? Back in the day they were made by enclosing a thick stack of newspapers in two vinyl squares and stitching around the edges. I made this "modern version" for camping by sewing batting onto two layers of vinyl tablecloth, right sides together. I left one side open, turned inside out, stitched closed and Voila, no more sitting on damp picnic table benches!