The first Obfuscated C Code Contest, in 1984, allowed entries of up to 512 bytes. This one, from an author who asked to remain anonymous because of a well-known connection to the C language, prints "hello, world!" by defining its own function named read that actually writes.
Every piece of it is a joke about something true. The string literal "]<i;++i){--i;}" is indexed with the integer i instead of the other way round, which C permits because a[b] means *(a+b). The expression '-'-'-' is zero, so read is called with file descriptor 0, and '/'/'/' is one. The loop body advances through "hello, world!" one character per call. In 2005 Thomas Scovell had it tattooed, the first contest entry to end up on skin. The contest's own copy adds a cast or two so modern compilers accept it; this is the 1984 text. The contest still runs.