Why are we reviewing an SD card? Usually, SD cards are just there--these days, high-capacity cards are dirt-cheap and nearly disposable. They're essential, but in the same way shoelaces are essential--you replace them when you need to, but you don't give them a lot of thought. Eye-Fi's new Direct Mode for its X2 line of SD cards, though, is different.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.