/*
 * This code is rather messy, but I don’t have time right
 * now to clean it up as much as I would like.
 * But it works, so I’m happy. :-) jpw
 */

Source: Direct link to the source code
Software: OpenBSD
Programming language: C

/* We changed phase but ESP shows bus service,
 * in this case it is most likely that we, the
 * hacker who has been up for 20hrs straight
 * staring at the screen, drowned in coffee
 * smelling like retched cigarette ashes
 * have miscoded something… so, try to
 * recover as best we can.
 */

Source: Direct link to the source code
Software: Linux Kernel
Programming language: C

/* FIXME: This algorithm sucks. I need to be shot for
 * writing such atrocious code. Grr. */

Source: Direct link to the source code
Software: Flood – a profile-driven HTTP load tester
Programming language: C

/* Try to suicide with a SIGABRT */
[...]
/* Still here? Try to remove any signal handlers */
[...]
/* Still here? Try to suicide with an illegal instruction */
[...]
/* Still here? Try to at least exit */
[...]
/* Still here? We’re screwed. Sleepy time. Good night. */
  while (1)
    /* Try for ever and ever */
    ABORT_INSTRUCTION;

Source: Direct link to the source code
Software: uClibc – a Small C Library for Linux
Programming language: C

# all this junk below just to conditionally load a module
# sometimes even perl is braindead…

Source: Direct link to the source code
Software: Net-AIM
Programming language: Perl