The nc utility, a "damn useful little backend utility" begun 950915 or thereabouts, as *Hobbit*'s first real stab at some sockets programming. Something that should have and indeed may have existed ten years ago, but never became a standard Unix utility. IMHO, nc could take its place right next to cat, cp, rm, mv, dd, ls, and all those other cryptic and Unix-like things.
Funny I've spent three years at DeVry, and three years before that dicking around with shell scripts, and never learned of netcat. Much like Forth, it's something I wish I knew about and could explore, back when my mind was still young and plsatic.