Huckleberry Finn means that I am Finn as you know. First I thought to be just Finn, but it sounds so stupid that I abandoned it. I read Mark Twain's Adventures of Huckleberry Finn when I was 8 or 9, of course.
Finn MacCool would have been cooler.
I said it somewhere else too, but Lewis Trondheim is a French cartoon artist. It's not his ral name, but I have no idea what his real name is. Anyway, I just like the sound of it, and I once used it as a password somewhere, and now it's become my name for this forum.