"Good old Martha taught us that rather than buying those ridiculously expensive anti-slip mats for a rug, just turn it over and run a few lines of acrylic-latex caulk every 6 inches or so. Let dry and flip over and your rug wont be going anywhere!"
Great idea for a large back yard: Use your solar lights. They aren't just for the ground! Take a 2x4 and cut them into squares to fit the existing fence posts. Using galvanized screws - not nails - to screw a "L" bracket to the underneath base. Then on top, screw on the stake.