Terry P wanted to see this video again. (That's him dressed in a jacket with a hood flying the plank.)
From the video description:
This is a homemade, radio controlled, slope soaring glider. It's made from two coroplast (corrugated plastic) election signs folded over and taped together. It has three carbon fiber arrow shafts taped inside to form the spar and another spar is taped to the bottom to form the "fuselage". At the front are lead weights in a rubber cover and at the rear, the coroplast fin is taped and glued to the shaft. The plane weighs 30 ounces, ready-to-fly.
This is the second day for this plane, and the wind here is about 30 to 40 mph. It's blowing about 20 to 30 degrees off perpendicular to the slope--from the pilots' right. For a total experiment using TLAR ("that looks about right") design techniques, this plane flies far better than it has any right to fly.