You see them on the video shelves, with titles such as Shadow Tracker, Psycho Girls, and The Blair Witch Project. Skeptically, perhaps, you rent one and slip it into the VCR. Hey, you think, this isn't so bad--sometimes actually quite good. Suddenly, you discover that there is a whole range of movies from filmmakers operating outside the studio system that have their own attractions that the big budget fare can't match. You have,...