Fusion Reactor
Normally, if a grown man talks about building a fusion reactor and wants your 13-year-old to hang out in his garage, we'd expect you to smile, back away slowly, and perhaps alert the authorities. But, if that man is Microsoft program manager Carl Greninger there's no need to run. The science fanatic recruited a team of teens, as young as 13, and worked with them to build a Farnsworth–Hirsch Fusor -- a (comparatively) simple nuclear reactor that smashes together atoms and produces neutrons. Check out the nearly 20-min video after the break to watch a bunch of high school kids generate ball of ionized plasma. And to think, all that's in your garage is that '65 Mustang you swear you're gonna restore one day.