One of the attendees at my last event in Greensboro, NC may have gone a little overboard with his car, but at least he's got the right message. ;-).
A few of note (since the picture is blurry)
One I'd never heard before:
"Stop Mad Cowboy Disease"
"John Kerry – Bringing complete sentences to the White House"
Most Debatable: (Thank Florida for this one)
Least Subtle: (Hmm… where do you go with this one?)
"Bush is a dumbass"