The otherwise-useless skill I've picked up from working in a photography studio: Untangling and elbow-winding a kinked extension cord. It's a pain in the neck to do, but after each and every shoot I have to go about the room collecting and organizing them.
Which is why this RoboReel Power Cord System is looking good to me. When I first saw it, my kneejerk reaction was "That's ridiculous and bulky, who would want that?" but quickly came to realize how much time I'd save in the studio alone. For those in shop and garage environments it's bound to be even more useful and, with the ceiling mount, out of the way. And I dig the built-in safety features you'll see in the demo vid:
P.S. For those of you using compressor-driven tools, the company is working on an Air Reel variant; for those of you with lawns, their Water Hose Reel can be rigged up for hoses and sprinklers.