The Live High Five challenge from KLM is a fun campaign that encouraged people to high five someone in a completely different country, with the aid of technology.
KLM set up a screen and a camera in public places in both Amsterdam and New York, so that each person got the chance to win a trip to the opposite location. People were challenged to high five one another at the exact same time, and the Live High Five machine measured each person's accuracy and timing. In the end, the best high fivers were rewarded with tickets to New York or Amsterdam. The simplicity of the fun travel campaign naturally drew crowds and created a ton of good energy that made other people want to get in on the action themselves.