Everybody remembers CRT (cathode ray tube) televisions and computer monitors, and many people still have them, but they've become increasingly uncommon these days. You know, the old, fat sets that weighed a ton? They've been mostly phased out by the thinner, lighter HDTV sets, but surely you still remember lugging those things out from Best Buy and dumping them in your car, dragging them home, and then slamming them into the entertainment center and screwing in that stupid-ass tiny co-axial cable screw into the back of the hulking mass, struggling to get a good grip on it. It was the CRT hum.