Sex of a Fly
A woman walked into the kitchen and found her husband walking around with a fly swatter.
"What are you doing?" she asked.
"Hunting flies," he responded.
"Oh. Killing any?" she asked.
"Yep, three males, two females," he replied.
Intrigued, she asked, "How can you tell?"
He responded, "Three were on a beer can, two were on the phone."