We know teenage boys need their privacy, but this is ridiculous. Justin Beckerman, 18, of New Jersey, has built himself a fully functioning one-man submarine, capable of diving to a depth of 30 feet. Beckerman will be able to explore both his local lake and his own inner depths in this high-tech craft, which has a communications system and an ultra-bright light to illuminate his surroundings. His parents must be very proud. But they're saps for letting him build it. You can't make a kid do anything when he's 30 feet under the surface of a lake.