Great posters?

What great clever posters are out their that catch your eye and are clever? Eg Guiness? Drink driving etc

Good question though I either don't look at posters or else there are not any eye-catching ones that I pass. I realise you probably have billboards in mind but it prompted me to think about posters that were around in my youth.
Back in the late 1960s some of us used to read the 'underground' newspaper 'International Times', which was often referred to as 'i t ' (in a particular italic font). There was an eye catching poster provided to vendors saying simply "You can get it here".
There was another I vaguely recall - sorry but that is a feature of living through the late 1960s. I can't remember the image on it - probably some hippie type - but the words were "We are the people our parents warned us against". That was SO true. It still makes me proud to this day .... :-)

Check out http://www.viewposters.com

They have plenty of posters. You could do slideshow too. It may give you ideas about what catches the eye.