A Russian boyar (baron or some such title) who needed a ride from one city to another in the middle of a winter, when there was lots of snow. He went to an inn where all the izvoshchiks were, and they all turned their heads when he asked for a ride... except one, who said he's going that route for twenty years. When they passed half of the way, the carriage hit a nasty bump and rolled over. - What's the matter, don't you know about this bump? Didn't you say you ride here for twenty years? - Yes, sudar', I do, and I roll over each time!

Now why is this a programming joke?

Haven't you ever met a programmer whose major quality is that he's got lots of experience... in doing the same thing over and over? And chances are, the idea of fixing a few things in that same old never came up.