Endlessh: An SSH Tarpit
 I opened up port 22 once so that it connected (without crypto) and issued the phrase,YOU ARE STANDING AT THE END OF A ROAD BEFORE A SMALL BRICK BUILDING.
AROUND YOU IS A FOREST.  A SMALL STREAM FLOWS OUT OF THE BUILDING AND
DOWN A GULLY.>and if they typed in something it would continue to play the game.  After hundreds of thousands of automated SSH worm probes over several months, an actual human did connect and play the game for a few minutes!  But even this triumph was short lived, they did not even play it to the end to see if something interesting might be unlocked (it would have been an invitation to contact my email address).