A 3V battery pack may not be enough to power Iron Man's armour, but it's all the juice you need for this incredible homemade 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]