These are all my test leads used for my scopes and meters, I got tired of digging through a mass of tangled, jumbled up mess in my toolbox looking for the one I wanted, so I hung them all on the wall, now I can grab the one I want with ease.

Spark plug starter, don't laugh, I put this together eighteen years ago, and I have used it ever since, an old Datsun 1600 4cyl head bolt, and a silicone plug boot siliconed to the bolt. This thing works slick for installing spark plugs, I tried other methods prior to putting this together, the piece of fuel line trick, and actual tools you could buy made just for it, and I never liked any of them. I have never cross threaded a plug with it, it provides the proper feel when trying to thread the plug. It gives enough while turning that its easy to tell if the plug doesn't hit the threads properly, and it bends easily enough to approach the hole at an angle. I never have to see the plug enter the hole to get it lined up and get it to thread. With this, and my 3/8" air ratchet, I can swap out a set of plugs on a Chevy pickup small block in about 15 minutes.