Short version.
When I first started coming to CC, registering a nick was optional. At the time, I used kakiss16 as my screename just about everywhere. Well, it wasn't a very christian name, so I soon decided to stop using it.
So, I was quite a trouble maker back in the day. Most of you are probably not familiar with the old setup, but there used to be temporary (momentary) kicks at the mod's disposal alone with IP bans. Well, I was quite a trouble maker back in my teen years and pushed more than a couple of the mods buttons. There was one in particular who I would perpetually hassle; his nick was ThunderBolt2000.
Well, as I figured it, if Thunder Bolts, then Lightning Claps. And thus my nick was born, registered it shortly after and well, the rest is history(or should I say part of the long version). I have since used it in several variations, primarily the super shortened form lghtngclp.
I don't think I'd change it, though it's long, people just get confused with "lghtngclp"; hopefully the length doesn't annoy too many people.