Maker's Mark has a marketing program where they tap top customers to be "Ambassadors". In fact, my wife's stepfather is such an Ambassador. They sent him a beautifully designed folder with a "personal" letter from the president of the company, a bunch of Maker's Mark business cards with his name and status (to pass out to friends), and most clever of all, a "birth certificate". This certificate announces the "birth" of a "newborn Maker's Mark barrel" that has his name etched onto it. This 50-gallon barrel will mature in 6 - 7 years and he'll be able to purchase bottles of it from his personal barrel. He can see the barrel (with his name on it) online.
As crazy as this all sounds, my father-in-law is pretty excited about it. He's been talking about it all weekend. He's a true customer evangelist. He's telling his friends (and clearly his family).
This barely costs Maker's Mark anything at all, and yet has its best customers talking about it.