Saw an excellent one the other day:
“I bet Jesus used His turn signals!”
Almost as good as the only one I’ve ever actually placed on a car I owned:
“Ignore alien orders”
Jesus loves you
Everyone else thinks you’re an asshole
I love that one!
Mean People Suck
[sub]Nice People Lick[/sub]
and
Honk if you love Cheeses
(y’know, as opposed to “honk if you love Jesus.”
One I saw a long time ago said simply “This Is a Bumper Sticker”.
I’ve always seen “Nice people swallow”
Just to let you know, I bet you could find 20+ pages of bumper sticker threads if you searched the archive.
My favorite one was the bumper sticker my parents had on their car for several years. You know how some people have the sticker that says “I love my cat” with a heart in place of the word “love”. Now replace that heart with a spade.
“Never underestimate the power of stupid people in large groups.”
“I don’t love you anymore since you ate my dog.”
In the spirit of, I 
NY
*I 
My Wife
I 
My Dog*
Sold as Gallahger Stickers, or something like that…
I’ve seen both, but I think your version is probably more popular, **Cisco]/b]. My cousin’s ex-boyfriend had the “Nice people lick” sticker on his car. I’m going back and forth on which version I like better.
My mother had a “No Comment” bumpersticker on her VW Micro-Bus in the seventies. Sweet.
“I love cats …
they taste just like chicken!”
Probably not as humorous to most, but I was nearly in tears when I saw it for the first time. I still laugh out loud when I see one.
Forget about world peace… visualize using your turn signal.
I took an IQ test and the results were negative.
Honk if you love peace and quiet.
If Barbie is so popular, why do you have to buy her friends?
Save the whales. Collect the whole set.
Madness takes its toll. Please have exact change.
I used to have an open mind but my brains kept falling out.
All those who believe in psychokinesis raise my hand.
Nuke an unborn gay baby whale for Jesus.
Visualize world peace… through maximum firepower.
Dog is my co-pilot
How can you trust me with a child if you can’t trust me with a choice?
Sure, it’s funny until someone gets hurt, then its hilarious!
Don’t postpone joy
If you really love someone, set them free.
If they don’t come back, hunt them down and kill them.
NEVER get behind a VW bus!
God is my co-pilot, but the devil is my bombardier.
**You can fool some of the people all the time,and those are the ones to concentrate upon.
If I save time, when do I get it back?
I am free of all prejudices. I hate everyone equally.
Take my advice, I don’t use it anyway.**
My favorite one is a variation on the “Jesus” fish. After you’ve seen the one with “Ichthus” in Greek and “Jesus” in english, followed by the one with feet that says “Darwin” and the ones with Darwin and Jesus attacking each other, it’s kind of a relief to see one that says “Ghoti”. If I was gonna put one on my car, that’s the one I’d choose.
“I Hate Bumper Stickers”.
Philosophize before you Proselytize