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.