Best and Worst Marketing Ideas . . . Ever Take a cue from these 13 killer campaigns--and 5 flops.

Some marketing efforts manage to hit the ball out of the park. They resonate with the consumer, generate tremendous buzz and even permeate pop culture, becoming part of our lives and linguistics.

In a rather unscientific manner, we've gathered more than a dozen of these iconic campaigns and consulted a variety of experts to explain why they were so great. Here's a recap along with the lessons that can benefit you and your business.

Best making the best of a bad image: Las Vegas' "What Happens Here, Stays Here" campaign
After a failed attempt to promote itself as a family destination, Las Vegas finally embraced its Sin City image with its "What happens here, stays here" advertising campaign, launched in 2003. It's still going strong: 2007 marked the city's fourth consecutive year of busting tourism records. "It resonated because it's what people already believe," says Laura Ries, president of marketing strategy firm Ries & Ries.
Lesson: Try to turn negatives into positives.