Back in January 2007, the Bush administration was urging the world's scientists to explore the possibility of deploying giant space mirrors that would block sunlight from reaching the Earth and hence reduce global warming. (Really.) The thought here was that this might work as a decent last-ditch save-the-planet gambit if we couldn't get our collective acts together and reduce greenhouse-gas emissions quickly enough. One of the options under consideration, as it happened, involved "thousands of tiny, shiny balloons." Now, I confess, there may have been some snickering from the TNR peanut gallery at the time, but maybe I was just underestimating the power of shiny balloons, at least judging by this Fortune report about a startup firm that's developing a balloon-based solar plant:

It sounds like something out of one of those do-it-your-self magazines: Stitch together two buck’s worth of thin-film plastic--the stuff potato chip bags are made of--stick in a photovoltaic cell, inflate with air and, voil