Cardboard WiFi Antenna Upgrade

An anonymous reader writes "A British company called Tritium is marketing a piece of cardboard with metal foil on one side. You order it for under US$25, shipping included, and you get a flat envelope with the cardboard. Cut it out, shape it into a parabola and snap it into the little stand. Then slip it over your current antenna. It is advertised to extend the range of your current antenna by 2 to 3 times. See their website for more information on the cleverly named Tritium Flatenna."