You'll laugh at how well road signs work to illustrate movies we are all familiar with. Unreality magazine has a list of 15 posters that mashup films with common road signs gleaned from the Photoshop masters at Something Awful. Link
Most of those are really good!
Abusive comment hidden.
(Show it anyway.)
Clever, but not what I'd call particularly funny.
Abusive comment hidden.
(Show it anyway.)