Downsize your pocket cargo with a custom-fit keychain. Editor Sean Captain ditches the ring and uses more tool than necessary to trim a small bolt to just the right size for his set of keys. (For a slightly different take on the project, see the site that inspired us: carlitoscontraptions.blogspot.com).
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.