1. Code that is overly tense and unmaintainable. “Perl may be a handy program, but if you look at the source, it's complete joe code.”
2. Badly written, possibly buggy code.
Correspondents wishing to remain anonymous have fingered a particular Joe at the Lawrence Berkeley Laboratory and observed that usage has drifted slightly; the original sobriquet ‘Joe code’ was intended in sense 1.
1994 update: This term has now generalized to ‘<name> code’, used to designate code with distinct characteristics traceable to its author. “This section doesn't check for a NULL return from malloc()! Oh. No wonder! It's Ed code!”. Used most often with a programmer who has left the shop and thus is a convenient scapegoat for anything that is wrong with the project.