We used vinyl cloth-backed tablecloths in the largest standard rectangular size 54" x 90".  These cost about $2.50 and made 9 situpons per tablecloth. You can also use vinyl sold by the yard that's not too expensive. Here's how to do it: Pre-cut the tablecloth into nine sections according to the picture at right using pinking shears along the gray lines shown in the picture. Discard the side edge pieces since the corners are not square and it's extra fabric anyway. Each section will be 15" x 30".  Fold each section in half so that you have a 15x15" situpon. Stuff folded newspapers inside, or use squares of donated carpet padding that you have precut to 13"x13" sections.      Use a hole punch to punch holes about every inch all the way around about a half inch from the edge. Depending on the age and abilities of the girls, you can have them punch the holes, or you can help them. Use yarn or string to sew around. Girls can use an overlay stitch or a straight stitch if they prefer. You may need to put a piece of tape on the end of your string to make it easier to insert through the holes. Brownies should be able to sew around and tie it off by themselves.  Have each girl write her name on her situpon using a permanent marker, or decorate it with paint pens.     Have fun making your Girl Scout situpon!