There’s a very funny, often silly, and oddly healing movement called “Complaints Choirs.” Wikipedia explains it as “a community art project that invites people to sing about their complaints in a choir together with fellow complainers.”
The Kvetch Kakophony is similar in affect, but far less artful.
One person is the conductor. Everyone else stands in a choir-like array. When the conductor signals, everyone starts singing their complaints about whatever they feel like complaining about. At the beginning, they might start out singing to a particular tune, like Hava Nagila or Take Me Out to the Ballgame. After a while, they should be encouraged to change to any tune they feel like complaining to, regardless of what tune anyone else is using. The conductor can get as conductor-like as she so desires, getting the choir to sing more loudly or more quietly, appointing people to be soloists or to sing duets etc. Singers can choose to sing in whatever language compels them, or in complete gibberish. No rhymes or reason, either, are required. Kvetching noises are encouraged.