I once worked with an industrial engineer who worked with a cookie manufacturer. The cookies were on a conveyor system. The conveyor ran through the oven. The cookies baked in the time it took to get from one end of the oven to the other. Then they went up a ramp to a serpentine series of conveyors that ran along the ceiling to cool.
At the end of the process was the bagger. This was the part of the system that sometimes broke. They could not stop the line otherwise cookies in the oven would burn. So cookies backed up. If they backed up too far, they would overflow the conveyor and it would start raining cookies: every 6-year-old’s fantasy dream.
I guess for adults, raining beer is probably equally enjoyable.