Bobby McFerrin demonstrates the power of the pentatonic scale, using audience participation, at the event "Notes & Neurons: In Search of the Common Chorus", from the 2009 World Science Festival, June 12, 2009.
The point of the video is to show that people naturally know the pentatonic scale. He sings the first two notes for them, both of which are in the Db minor AND Db major scale. The third one is yet undecided. If the next note goes up a half step, the song is Db minor. If it goes up a full step, the song is Db major. The entire audience chose to go up a full step and turn the song into Db major, sticking with the pentatonic scale.