An old fellow down my road has a good sense of humour. In the back window of his car it says:
"Yes, as a matter of fact, I can drive slower."
Saw one down Southend seafront last summer which, judging by the amount of pink on show and the fluffy dice, obviously belonged to a young, female driver with a sense of humour. It read: "Babe on board."
I've seen the Grandkids one DJ, made me smile.
Other humourous ones are;
"American by birth, Southern by the grace of God."
Seen all over Dixie.
And the ever popular one in heavily Hispanic areas.
"Will the last American to leave Miami/El Paso/Brownsville/San Diego, please switch off the lights!"
Here are some of the funny bumper stickers I went across:
A friend doesn't go on a diet because you are fat.
There are no stupid questions, just stupid people.
The only reason people get lost in thought is because it's unfamiliar territory.
The average woman would rather have beauty than brains, because the average man can see well than he can think.
Strictly speaking not a bumper sticker, but on a small fruit delivery van in Fenchurch Street today I noticed a proper sign written message a la "No tools left in this van overnight."
It said, "No bananas are left in this van overnight."
Saw a parked van last week with the words on the rear door: 'This van is driven by a blind man.' As I drove past I was relieved to see it belonged to a company selling blinds, curtains etc. Good advertising. It certainly made me look.
Had a e-mail from a mate a year or so ago about signage on vehicles. Struggling to remember them, but one that stuck in my mind was the one for the Australian 'dunny' truck which read: 'Yesterday's meals on wheels.'