There may be no gadget as versatile and useful as the Doctor's sonic screwdriver from "Doctor Who." It can open (or engage) locks ranging from rusty old padlocks to digital keypads. It can reprogram computers and repair old wiring. In a pinch, you can use it as a weapon and knock people unconscious with it or pair it with a power source to zap Daleks or Cybermen. What can't it do?
Well, it can't open anything that has a deadlock seal on it. What's that? It's a plot device designed to make it harder for the Doctor to escape a situation. In other words, a sonic screwdriver works in any situation except when it's not convenient to the plot. We'd love to have this kind of device. Most of the time, it will work perfectly. When it doesn't work, you know you're in a really important situation.
While the Doctor has had decades to become adept at wielding the sonic screwdriver, his human traveling companions have also put it to use in a pinch. That gives us hope that this incredibly flexible tool would still work in the hands of a novice. We eagerly await the full-scale production of the device -- no toolkit should be without one.
Did we leave out your favorite sci-fi gadget? Let us know what your pick would be!