CAN'T SPELL
Mr. & Mrs. Jones were eating breakfast one morning and Mrs. was reading a letter while she ate.
Suddenly she looked up suspiciously at her husband.
"Henry," she said, "I've just received a letter from mother saying she isn't accepting our invitation to come and stay, as we do not appear to want her. What does she mean by that? I told you to write and say that she was to come at her own convenience. You did write to her, didn't you?"
"Er, yes, honey, I did," said the husband. "But I couldn't spell 'convenience', so I substituted 'risk'."
(last time we checked, this husband was still recovering from his injuries.)