Basically if you put a bunch of bored natives together in the presence of something that can be hit like a drum, someone will start drumming, and everyone else will join in singing and dancing. It's a wonderful show of tribal spirit. And it's a reminder that you don't need a whole powwow and a $1500 Drum manned by experts. You can flip over a bucket or a garbage can and get fairly similar results. What matters is the support of community ties.
By the way, the hat game? The version I first encountered was a show of horsemanship, in which a rider would attempt to snatch an object off the ground with their teeth. This version, which looks more recent since it works indoors, is probably older because horses have only been available for a few centuries.