As night gave way to daybreak at the Supernova Sukkot Gathering in southern Israel, Ofek Baribi turned to Eden Abdulayev and gave her a soft kiss on the lips, and the pair headed to the dance floor.

OJAI, California — In a circular room drenched in winter sunlight, a group of young men and women sit cross-legged on the floor. Their eyes are mostly closed. Some lie down prone. Others enlace one ...