My personal favourite from here in the UK is "Changed Priorities Ahead". Quite philosophical but also worrying - in fact, I find I'm totally preoccupied with worrying about what my priorities were and just how they might change after passing the sign. And here in Wales there's more entertainment to be had with the juxtaposition of Welsh and English - what exactly is a slow araf, for example? But in terms of grammar, both my husband and I have spent many moments discussing how much better they might have phrased the recent "Don't Drive Tired".