Camping DIY: Pop-up camper mod. 6 PVC pipe mounted on camper to hold outdoor carpet. It is connected to the frame with internal stainless steel carriage bolts and hardware. A cap on the left and screw plug on the right should keep the carpet nice and dry.
Portable light post made with PVC pipe! While this one probably isn't a geocache, it would be a cool idea to put a mini light post out in the middle of the woods as a cache. A bit like the lamp post in Narnia.