From The Economist:
Three prisoners in the gulag get to talking about why they are there.
"I am here because I always got to work five minutes late, and they charged me with sabotage," says the first.
"I am here because I kept getting to work five minutes early, and they charged me with spying," says the second.
"I am here because I got to work on time every day," says the third, "and they charged me with owning a western watch."
Why do secret policemen work in groups of three?
One to read, one to write, and one to keep an eye on the two dangerous intellectuals.