Back in my student days long ago, a friend of mine who was working on a very difficult assignment hatched a plan to include a SIGSEGV handler that would print "NFS server not responding, still trying..." for use on the day when we had to demo the results to the TAs. The NFS system was pretty flaky and his hope was that the TA would move on to the next demo and get back to him, giving him time to fix whatever problem was happening. Not sure if he actually put it in though.

Back in my student days for DOS-based labs we just did

  char foo[640*1024];
  int main(int argc, char ** argv) { return 0; }

When ran, it made the OS say "Out of memory" and then it was lab assistant's headache to unload all that resident stuff that was sitting there and eating good 20-30% of available RAM. They typically opposed to doing that, so the TAs assumed the program actually worked. The end :)

I must be the only moron who used to be eager for others to see his programs. No teacher ever looked at it long enough to appreciate it though; I quickly established a reputation as a computer show off and the teachers were dismissive of me, spending more time with kid who actually had problems.

>> I quickly established a reputation as a computer show off

Hmm ... :)