Melt, a restaurant near Cleveland, Ohio specializing in gourmet grilled cheese, might have one of the coolest marketing tactics around. If a loyal customer gets one of three approved Melt logos tattooed somewhere on their body, they get 25% off their purchase for life.
(this one being the most popular)
As of today, over 400 people have taken the restaurant up on their offer. More details are available on their website and Facebook page.
Not only will these people be customers forever, but they are sure to tell other people about the restaurant as well. Word of Mouth at its finest.
Hats off to the team who thought of that one.
Disclaimer: The food is delicious. A stunt like this probably wouldn't work if your place is shitty.
