Oh, it is a little game where you attempt to fulfill premade challenges for points. For instance, some one may make the challenge, "take a picture with a stranger in a red shirt" and make it worth 5 pts. They may also add bonus objective to the challenge to make the challenge worth even more points, such as getting the stranger to make the Vulcan salute (Live long and prosper) which would be worth an additional 3 pts, bringing the total points for this challenge to 8.
The challenges don't always have to include other people or pictures. They can be anything from saying something silly when you get off the plane to hording as many packets of peanuts as possible to finding items with foreign nations' flags on them in a gift shop. The main rule is that you cannot others about the challenges. That makes it too easy and half the fun is getting people to do silly things just by charm alone. And of course, try to be reasonable. Never put a challenge that will get the person arrested or start an international incident.