As the asymmetrical groove of the “Ritual of the Rival Tribes” chugged into motion, men in their 20s and 30s began to bob their heads. Soon, movements grew more demonstrative (aided by a couple of professionals planted in the crowd). In the amorphous sections of “The Sacrifice” a few couples gamely tried to slow dance. The violent “Glorification of the Chosen One” briefly spawned a hardcore-style mosh pit in the increasingly steamy hall.