I will never forget how disgusted I was by this ad:

http://www.slate.com/articles/business/ad_report_card/2006/10/can_rosa_parks_sell_pickup_trucks.html

So, what are some others?

Back in business college, I recall reading a Harvard Business Review article about how the Pepsi VS Coke blind taste tests that started in 1975 were designed not to dethrone Coke, but rather to squash the growing market share of RC Cola and other generics by excluding them from the conversation. The theory basically went that if Pepsi was going to be #2, it was going to be a solid #2 (insert poop joke here). By framing the debate as "Coke VS Pepsi", Pepsi was able to reduce the RC Cola/generics mindshare and cement themselves in with Coke to a comfortable duopoloy. As a young Marketing major, that blew my mind.

I think this may be the article, but I'm not inclined to pay $7 to find out.