Having worked in multimedia nightlife event promotion (a fact I'm not entirely proud of), I know that while popularity may be fleeting, there are a shitload of restaurants and clubs that thrive on gimmicks, chicanery, and bullshit in general.
The Demachi location of Gyoza no Osho in Kyoto, Japan is the real deal. From the article in The Mainichi Daily News (via Tokyomango), Gyoza no Osho is a fast food chain serving up pot sticker dumplings, noodles, rice, and other traditional budget-friendly fare. The Demachi location is close to Kyoto University and Doshisha University, and as you can imagine, hungry students are plentful. Sadahiro Inoue, the manager at the Demachi location, has hung up a sign for the past 27 years promising free meals to those who promise to wash dishes for 30 minutes after eating.
He keeps in touch with many of his former dishwashers and thinks of them as family - much as an elderly couple took care of him and his wife when they were young, struggling newlyweds. He hopes that they go on to do good deeds for others. Stuff like this makes me still believe in altruism.