When I'm bored, I often think of ways to write new inefficient "Hello, world!" programs. These are some methods I've come up with:

Making the program go through the characters of the string "Hello, world!" one by one, generating random characters until it comes up with the correct one, then displaying it.

strcat()'ing many short strings containing parts of the string "Hello, world!"

Using many #define's, I've made a hello world program where the only code that wasn't preprocessor directives was "q foo lal lol rod b n s 19 y x n g r w r x a lal n lol x bar l x rofl".

Writing "Hello, world!" to a file, then using system() to display the text in the file using cat.

Transferring "Hello, world!" character by character through a local TCP/IP socket connection, displaying each character as it is received.

Using a separate thread to display each character in the string "Hello, world!"

And possibly some others that I've forgotten.