I saw some really cool pillows last spring in the Pottery Barn catalog, and wanted to create something similar ever since. These are made out of simple canvas duck cloth, and they are actually pillow shams. A lightweight pillow is tucked inside.
I got out my trusty craft paints, and free handed the designs, based on pillows in the catalog. Sprayed with Scotchguard, they should repel water and be fine under the porch.
Now we won't sit quite so far back in the chair.