There are four films at Sundance that venture, at least nominally, into the world of cults. Cult recovery (MARTHA MARCY MAY MARLENE), cult membership (HIGHER GROUND), cult discovery (THE SOUND OF MY VOICE), and cult leadership (RED STATE.)  But as the crowds swell in Park City, as bus load after bus load of excited devotees alight, something is clear: there are an awful lot of identical grey sweaters, blue lanyards, knit hats and striped scarves. Together but alone, the committed stand in line for days, freezing cold, blind with hope.