Betty's mother

Betty's mother was visiting her daughter and son-in-law Bill. Bill came home
from work and found six vacuum cleaner salesmen outside his house. He dashed in
and said, "Mom, there are six men outside who all claim they have an appointment
for a vacuum cleaner demonstration!"
"That's right," the mother-in-law replied. "Now you just show them all to
different rooms and let them start demonstrating."