A bean bag cover can be filled with beans to make a comfortable and inexpensive chair. All you need is some basic shapes of fabric and a zipper. The fabric should be fairly thick and tightly woven. Customise the fabric's colour and pattern to match the existing decor in any room.
Take each circle of fabric and sew a line of straight stitches 1/4 inch from the outside perimeter all the way around. Snip into the seam allowance with scissors around the edge--up to, but not through, the stitches.
Fold the rectangle of fabric halfway across the middle so that the two shorter ends are aligned with the "right" sides of the fabric facing each other. Sew a 12-inch line of stitches from the top of the piece towards the middle, leaving a 1/4-inch seam allowance. Flip the piece upside down and sew another 12-inch line from the edge towards the middle. You should have a seamed edge with a 12-inch gap in the middle. Press the seam and gap open with an iron.
Pin the zipper in position along the rectangular fabric's 12-inch gap, so that the right side of the zipper is facing you and the folded edges of the gap are placed over the sides of the zipper.
Top-stitch the zipper in place. Make sure there are no gaps between the stitches in the seam and around the zipper. Sew any gaps closed. Unzip the zipper.
Take one open side of the fabric loop you just created and pin a small section along the edge of one of the fabric circles with the "right" sides of the fabric together. Pin the seam all the way around the circle, easing the straight edge around the circular edge.
Sew the rectangular loop piece to the circular piece, keeping the stitches to the inside of the basting stitches around the circle. Repeat for the other circular piece, then flip the bean bag cover right-side-out through the open zipper.
To make the bean bag cover washable, create another cover from thin muslin to fill with beans and place inside the decorative cover. Set your sewing machine to a shorter-than-usual stitch length to prevent beans leaking out of the seams. You can use Velcro strips instead of a zipper.