I don't have a fence, but like this idea. Find old windows, replace the glass with mirrors and put these on your fence (if you can). The mirrored image of your garden on the fence will make your yard look bigger. It's an easy trick!
I think we Should do a craft day and Mass produce some of these Rubber Door Mats pressed into a concrete mold and later removed, to make stepping stones. There are lots of other smart concrete project ideas on this page.