On a crowded bus between Allston and Harvard, a man with a voice like Tom Waits with a tracheotomy started "singing" a very metal sounding song. He was not wearing headphones and appeared emotionally disturbed. Most of what he was mumbling was incomprehensible but the refrain was definitely "when you get up,you go down down".
After three or four awkward moments, we, the collective other bus patrons would wait for him to say "when you get up" an we'd all join in, "you go down down." It was awesomely cathartic, and everyone, including the driver and the mumbly man, appeared to be having a good time.