Baste a turkey
A State Police colleague of mine once received a call from a woman who asked him how to baste a turkey. After a stunned moment, he, being a fairly good cook, described the procedure. Then he asked,
'But why would you call the State Police to find out how to baste a turkey?'
There was only a slight hesitation before she replied, 'Well, you knew, didn't you?' and hung up.