Hello, World!
Every introductory programming book begins with a "Hello, World!" program, but this Louisana Tech site takes that concept to the extreme. Almost 200 different examples using 200 different languages.
Sites like this don't make me miss college. I can't believe I had a whole semester of Lisp and Prolog.
Lisp
(DEFUN HELLO-WORLD ()
(PRINT (LIST 'HELLO 'WORLD)))
Prolog
hello :-
printstring("HELLO WORLD!!!!").
printstring([]).
printstring([H|T]) :- put(H), printstring(T).