Scenario 1: Sport


Sixty miles up, you sit in a chair on the open deck of a small rocket, admiring the stars above, the Earth far, far below. The vacuum beyond your visor is cold, but it would boil your blood if your pressure suit failed. You give your parachute straps a reassuring pat. It's utterly silent. Just you and your fragile body, hovering alone above the Earth. "Space Diver One, you are go," crackles a voice in your ear, and you undo your harness and stand up. There's nothing for it now: You paid a lot of money for this.

Sounds too futuristic to be true? See below for a video of the Skyguard system taking out mortar rounds, artillery shells and rockets

Want some real home theater bragging rights? Instead of buying a projector capable of casting a 14-foot image at 1080p (progressive) resolution-the highest high-definition there is-build one yourself. After all, the front projector´s innards are simple: an LCD lit by a superbright lamp, and a few lenses to magnify and sharpen the image. Retail models start at around $800 and use proprietary $400 lamps that burn out every few years. But cheaper lamps work equally well, and none of the other parts are very expensive. Why not put one together yourself?