When I was a kid, I recall writing a very simple (think read a line, send a line, no select() so blocked unless the right order for read/send line operations took place). It was in C on Linux.

Having something appear on another computer was one of those magical moments in my career – like the first time I got BASIC on Apple II to print "*" all over the screen. Nothing much has come close since since – maybe a few "Ah ha" moments in Prolog, Lisp or Forth...