There may or may not be a God,
but if you don't stop reading this sign and watch where you're driving,
you'll find out soon enough.
There's probably no life
unless you stop worrying
and enjoy your God
My favorite so far gets the bus sign generator treatment:
Go see them all, and try your own hand at this if you wish.
p.s. A new reader, Eric, has a great post with theological bus options.