There have been two pop-culture tsunamis so far this fall: the build-up to the end of Breaking Bad, and the series of successfully attention-demanding antics by Miley Cyrus. Posturing at MTV’s Video Music Awards. Riding her “Wrecking Ball” video, naked, to unprecedented first-day views. And now, appearing on Saturday Night Live, as both guest host and musical guest. Nice twerk if you can get it.