First get their attention. Sequentially. Unexpected humor helps - especially if it is visual. So is consistency: repeat the punchline, motto or promise in many different ads, parts of your blog, web site and on-site in your organization.
Contrary to the saying, "familiarity breeds contempt" instead it breeds acceptance. That's a big step towards buying. Out to Launch's Amy Corr offers these great examples that may make you laugh too. Also notice the way Holiday Inn Express offers guests a luxury shower experience that doesn't cost the hotelier anything more to provide. That's SmartPartnering.