On Saturday, July 5, at 6:40 p.m., the season finale of Doctor Who will go out on BBC1 to an expected audience of 10 million viewers. The specially extended 65-minute episode should be one of the most watched shows of the year in the United Kingdom. For casual sci-fi viewers who might not get what all the fuss is about, this preview will stack up some background data to prime this weekend's big sci-fi send-off for The Doctor and his Tardis crew.