Maybe the best piece of Ass-vertising I've ever seen.

(click image, via) Cheeky! Yes, this is a real ad placed on buses for the Colorectal Cancer Association of Canada. Compare it to the most blatantly gratuitous piece of Ass-vertising ever (nsfw). Last March, the Association asked Canadians to photocopy their butts and post them on facebook. This is a better idea. One nit: Those most at risk for colon cancer—people 50+—might be turned off. Ad agency: Ogilvy Montreal. Want more ass ads? Scroll through my Ass-vertising archive.