Bonesnap

John was a salesman’s delight when it came to any kind of unusual
gimmick.  His wife Marsha had long ago given up trying to get him to change. 
One day, John came home with another one of his unusual purchases. 
It was a robot that John claimed was actually a lie detector.  It
was just about 5:30 that afternoon when Tommy, their 11 year old son
returned home from school.  Tommy was over 2 hours late.

“Where have you been?  Why are you over 2 hours late getting home?”,
 they asked.
 
“Several of us went to the library to work on an extra credit
project” said Tommy.
 
The Robot then walked around the table and slapped Tommy, knocking
him completely out of his chair.
 
“Son, this robot is a lie detector, now tell us where you went after
school .”
 
“We went to Bobby’s house and watched a movie.”
 
“What did you watch?” asked Marsha.
 
‘The Ten Commandments.” answered Tommy.
 
The Robot went around to Tommy and once again slapped him, knocking
him off his chair.
 
With lip quivering, Tommy got up, sat down and said, “I am sorry I
lied.  We really watched a tape called Sex Queen.”
 
“I’m ashamed of you Son,” said John.  “When I was your age, I never
lied to my parents.”
 
The robot then walked around to John and delivered a roundhouse
right that nearly knocked him out of his chair.
 
Marsha was bent double laughing, almost in tears.
 
“Boy, did you ever ask for that one!  And you can’t be too mad with
Tommy.  After all, He is your son!”

The Robot immediately walked around to Marsha, and slapped her three
times.