Use an old tire to create a small backyard pond. My kids, 3 sons, have been helping with yard work and planting. They keep asking for a pond. I think this is a great DIY project to do outside with them. Looks simple.
a hinged full length mirror from IKEA (Stave mirror - that is x hides jewelry storage -- brilliant idea from The Girl on the Go! I would use a thin sheet of plywood cut to fit behind the mirror so I don't put so many holes in the wall.
Mow strips can be made from any solid material used to separate the lawn from a planting bed. They allow a law mower to trim the grass all the way to edge of the lawn without having to use a string trimmer.