I have a mezuzah on my car's A-pillar. I was explaining what it is to a friend and found this joke:

"A What?"

After years of hard work, a man who has finally made his
way in business decides to treat himself and buys an
extravagance: A new Lamborghini. However, after
buying it, he feels a bit guilty. So, he goes to the Rabbi
of the Orthodox synagogue in his town and asks for
a mezuzah for his Lamborghini.

"You want a mezuzah for what?" the Rabbi asks.
"It's a Lamborghini," the man replies.
"What's a Lamborghini?" asks the Rabbi.
"A car, an Italian sports car."
"What? That is blasphemy!" the Rabbi shouts.
"You want a mezuzah for a sports car? Go to
the Conservatives!"

Well, the man is reluctant, so he waits a few days but finally
goes to the Conservative Rabbi and asks for a mezuzah.
"You want a mezuzah for what?" the Rabbi asks.
"It's a Lamborghini," the man replies.
"What's a Lamborghini?" asks the Rabbi.
"A car, an Italian sports car."
"What? That is blasphemy!" the Rabbi shouts. "You want
a mezuzah for a sports car? Go to the Reformed!"

Again, the man feels guilty, but finally he breaks down and
goes to the Reformed Rabbi.

"Rabbi," he asks, "I'd like a mezuzah for my Lamborghini."
"You have a Lamborghini?" asks the Rabbi.
"You know what it is?"
"Of course! It's a fantastic Italian sports car! Can I see it?"
They go out and the Rabbi carefully looks over the entire car,
finally settling into the driver's seat. "Well, this is fantastic,"
the Rabbi tells the man, "this car has dual overhead cams,
400 horsepower with a supercharger, a MacPherson front
end, and Koni shocks all around. I have only one question."
"What's that?"
"What's a mezuzah?"