"Nine Months Later" joke

Jack decided to go skiing with his buddy, Bob. They loaded up Jack's van and
headed north. After driving for a few hours, they got caught in a terrible
blizzard. They pulled into a nearby farm and asked the attractive lady who
answered the door if they could spend the night.
"I realize it's terrible weather out there and I have this huge house all to
myself, but I'm recently widowed," she explained. "I'm afraid the neighbors will
talk if I let you stay in my house."
"Don't worry," Jack said. "We'll be happy to sleep in the barn. And if the
weather breaks, we'll be gone at first light."
The lady agreed, and the two men found their way to the barn and settled in for
the night.
Come morning, the weather had cleared, they got on their way and enjoyed a great
weekend of skiing.
About nine months later, Jack got an unexpected letter from an attorney. It took
him a few minutes to figure it out, but he finally determined that it was from
the attorney of that attractive widow he had met on the ski weekend.
He dropped in on his friend Bob and asked, "Bob, do you remember that
good-looking widow from the farm we stayed at on our ski holiday up North?"
"Yes, I do."
"Did you happen to get up in the middle of the night, go up to the house and pay
her a visit?"
"Yes," Bob said, a little embarrassed about being found out. "I have to admit
that I did."
"And did you happen to use my name instead of telling her your name?"
Bob's face turned red and he said, "Yeah, sorry, buddy. I'm afraid I did. Why do
you ask?"
"She just died and left me everything."