I have always wanted to patent a scrolling-message-board for cars.
The message board would be located right above both the front and rear bumpers. The board would allow drivers to talk to one another on the road. Like when someone is "riding your ass" (as they say) you would choose from one of the 20-programmed messages:
"Please stop driving so closely to my bumper. Thank you."
Then the message would appear on the screen, and wa-la you have just successfully let the person know behind you that they are inconveniently riding your ass.
I would like to keep the message board polite. I am sure I could think up a slew of funny, off-color messages that we can all type to other drivers, but I would like to envision a freeway where we are all devout Christians w/ that fish symbol bumper sticker, and of course, we all have green grass.

more programmed messages:
Would you please turn your brights off?
Something is about to fall out of your trunk.
You drove off with the gas pump
Why are you flashing me?
You are hot. Praise the Lord & call me: 555-1234

programmed responses:
Thank you
Oh my!
I am flashing you because you left your cell phone at the gas station.
You are hot too. Lets stop at the next rest area.