Remember in high school, when your laziest teachers would invite in terribly ineffectual special guests to entertain the class, usually on Fridays right before vacation week? And while you'd be happy these guests freed you from any actual responsibility, you always wondered why "they" didn't just give you a Half Day, because no one wanted to be here anyway, except maybe the poor saps who'd been cajoled into thinking their expertise meant something to a room of indifferent clock-watchers?