An inmate at the local detention center was sitting in his cell playing solitaire.
Another inmate was watching.
Finally the kibitzer spoke up, “Wait a minute. I just caught you cheating yourself. “
“Shhh! Don’t tell anybody but for years I’ve been cheating at solitaire. “
“You don’t say! Did you ever catch yourself cheating?”
“Nah, I’m too clever. “
This joke is included in the Black Book of Jokes. You can order it from here.