A three volt battery pack may not be enough to power Iron Man's armor, but it's all the juice you need for this incredible home-made arc reactor. And if you don't believe me, just check out the instruction manual.
Granted, it's a bit more involved than your average DIY project—even your average arc reactor project—but it's also proportionally more awesome. You'll need a soldering iron, dremel tool, drill bits, a thin brass sheet, copper wire, and a whole lot more, and the assembly involves some higher-level craftsmanship. But if Tony Stark can build one in a godforsaken cave, surely you can clear out space in your garage. Full instructions and more nice pics await here. [Instructables]