Believe it or not, there is a
GNU version of the classic
hello world program. The GNU version includes a number of extra features, such as an
info documentation page, an option to use new ("Hello, world!") or traditional("hello, world") style outputs and an option to
check your mail.
The package I believe is partly supposed to be tongue in cheek, however it does serve a serious purpose as an example of how GNU programs are supposed to be structured: portable, internationalised, conformant the the GNU coding standards and with proper documentation.
The source code is over 2,000 lines long (8,000 including translations), amusing considering that GNU programs (such as Emacs) are often the target of accusations of bloat.