Choose your own shady spot. These pre-made sail shades come in triangles, right triangles and squares of high density shade material. We've always liked the look of them, but figured they would be super-pricey. Not so - prices range from $129.99 for at 12' triangle to $309.95 for a 18' square.
They can be stretched between trees, posts and buildings from the D-ring at each corner. The seamless extra wide fabric these are made from comes in seven colors. The same site also provides photos of residential installations, sample layouts and sells the installation hardware. Available from shadesails.com. Re-edited from an original post published 6.9.06