Trepanation, the practice of drilling or cutting holes in the skulls of living human participants, is apparently more common than most people suspect. It certainly has a few hardcore supporters, particularly among British eccentrics, as demonstrated in the documentary A Hole In The Head. Why would anyone willingly drill a hole in his skull? It depends on the culture. Some African tribes believe it has medicinal purposes, while medieval and Renaissance-era Europeans found it an effective treatment for insanity and/or demon possession. Contemporary Western trepanators suggest that it raises consciousness, despite medical evidence to the contrary and, well, common sense. Whatever the case, A Hole In The Head showcases plenty of enthusiasts and scoffers, offering a pretty good survey of the state of trepanation today. Presenting interviews with, and graphic footage of, several trepanators, some of whom perform the procedure themselves, A Hole In The Head begins compellingly enough—it is, after all, a film about head-drilling—but it becomes increasingly monotonous as it goes along. But what emerges from the wide-eyed, unconvincing accounts of the virtues of trepanation eventually becomes interesting in its own right, as most looks at obsessed types do. And, despite accounts of the procedure that are detailed enough to be considered instructions (remember, the skull has a soft layer beneath its surface that may feel like brain matter but isn't), the words that open the film may be the smartest: "Do not try this at home."