Mothers in law.
The ex mother in law was visiting ex hubby and I in LA with her husband. They drove to San Francisco up in Northern California which ex hubby and I had visited once. Round about the time we expected them to get there, they called us with the immortal line:

"We can't find anywhere to park. Is there anywhere near to the hotel we should park?"

Current mother in law on Christmas Day was showing her new camera phone off to the family. Out of her mouth:
"I'd take pictures, but I don't have any film in it. Where do you get film that small anyway?" Cue much howling from the family of various ages.

Friend of mine from California visiting us in York. While we're standing at the checkout she looked around and said:
"Well, everyone looks the same - I thought they'd be a different colour or something".

And this one from the husbands friend who is sat next to me!
(It's pissing it down with rain here)

Him - "So, what's the rain like in England?"
Me - "Er, rain"
Him - "Yes, but is it different"
Me - "Yes, raindrops are usually purple"
Him - "Oh fuck off!"
( Batshitmentalist is sane for once, Fri 7 Jan 2005, 20:26, Reply)