Seat cover for dining chair. Clean, simple wrap around design that fits snugly around legs with velcro. This would be simple to make by altering this DIY: http://www.athomeonthebay.com/2012/03/dining-chair-drop-cloth-slipcovers.html
Upholstery for the lazy girl! When decorating, always keep in mind that no-one's going to see the bottom/back/inside. This is only one small step up from wrapping a loose piece of cloth over a cushion, but it does keep the cover tidy and in place. So: lay that piece of grey denim you're never going to make a skirt from, face up on the floor. Put the cushion more or less in the middle.