This past month i was traveling on the east coast of Florida. I had asked several people in town what was happening on that Thursday evening and the answer I kept getting back was "Oh, its flip for your drink night at the La Quinta Bar..."
After several recommendations, I headed that way, ordered up a beer, and the bartender yelled over the crowd, "Heads or Tails?" I call "Heads" the coin lands on "Heads" and bartender hand me my beer and thanks me. No strings, no gimmicks, just walks away.
Second round, I call the "heads" again and viola, two free beers in a matter of 10 minutes...I look around see that its beers, cocktails, and wine; every beverage being ordered is having its price fate determined by a coin toss...
Brilliant! The place was packed, the town was a buzz about the promotion, and all 4 people who suggested I head that way eventually turned up as well - both locals and tourists loved the excitement of this 50/50 shot at something free. Interestingly enough, I found myself almost hoping to lose after 3 wins - guilty?!?
So simple, so viral, so successful!