@Klaxun Yeah anything that delves into ritual and liminal space might be interesting - the one i think im thinking of i think might be "The Ritual Process: Structure and Anti-Structure".
Also tracking down any book that goes into detail on trying to actually describe Happenings from the 60s/70s. To that end Id very much recommend Ringolevio: A Life Played For Keeps by Emmett Grogan following his work with The Diggers which is who Ken Kesey modelled himself on with his Acid Tests. Ringolevio is free as a .txt online on the diggers website. A lot of it is not going to be useful but still a wild read if you havent, but theres a few points that describe The Diggers events like The Invisible Circus and the Frames of Free Reference that are interesting points.
If you're able, tracking down any description of theatre events by Joseph Campbell, who irregardless of what anyone may think of his concepts on ritual, his events at the very least managed had some very beautiful concepts that were deeply affecting.