Reuse an old tree to make a log pathway in your garden. Good use of "yard" trees and other wood that can't be milled; works much better in climates without termites. Good drainage under the log rounds will make the path last longer.
Garden markers add personality to a garden and help you remember which row is tomatoes and which is peppers. Gather (or purchase) river rocks, some paint markers (pick up Sharpie brand at The Home Depot) and create these cute river rock plant markers.